Methods, compounds, compositions and vehicles for delivering 3-amino-1-propanesulfonic acid

ABSTRACT

The invention relates to methods, compounds, compositions and vehicles for delivering 3-amino-1-propanesulfonic acid (3APS) in a subject, preferably a human subject. The invention encompasses compound that will yield or generate 3APS, either in vitro or in vivo. Preferred compounds include amino acid prodrugs of 3APS for use, including but not limited to the prevention and treatment of Alzheimer&#39;s disease.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/246,894, filed Apr. 7, 2014, now U.S. Pat. No. 9,499,480, which is acontinuation of U.S. patent application Ser. No. 11/871,639, filed Oct.12, 2007, now U.S. Pat. No. 8,748,656, which claims priority to U.S.provisional patent application No. 60/851,039, filed Oct. 12, 2006, andU.S. provisional patent application No. 60/911,459, filed Apr. 12, 2007,all of which are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The invention relates to methods, compounds, compositions and vehiclesfor delivering 3-amino-1-propanesulfonic acid (3APS) in a subject,preferably a human subject. The invention encompasses compounds thatwill yield or generate 3APS, either in vitro or in vivo. Preferredcompounds include amino acid prodrugs of 3APS for use, including but notlimited to, the prevention and treatment of Alzheimer's disease.

BACKGROUND OF THE INVENTION

Alzheimer's disease (AD) is a progressive degenerative disease of thebrain primarily associated with aging. Prevalence of AD in the UnitedStates in 2000 was close to 4.5 Million. It was estimated that about onein ten individuals over 65 and nearly half of those over 85 are affectedby Alzheimer's disease. Approximately 360,000 patients will be diagnosedwith AD each year in the United States alone.

Clinical presentation of AD is characterized by loss of memory,cognition, reasoning, judgment, and orientation. As the diseaseprogresses, motor, sensory, and linguistic abilities are also affecteduntil there is global impairment of multiple cognitive functions. Thesecognitive losses occur gradually, but typically lead to severeimpairment and eventual death in the range of four to twelve years.

Alzheimer's disease is characterized by two major pathologicobservations in the brain: neurofibrillary tangles and beta amyloid (orneuritic) plaques, comprised predominantly of an aggregate of a peptidefragment know as AB. Individuals with AD exhibit characteristicbeta-amyloid deposits in the brain (beta amyloid plaques) and incerebral blood vessels (beta amyloid angiopathy) as well asneurofibrillary tangles. Neurofibrillary tangles occur not only inAlzheimer's disease but also in other dementia-inducing disorders.

3-amino-1-propanesulfonic acid (3APS, Tramiprosate, Alzhemed™) is apromising investigational product candidate for the treatment ofAlzheimer's disease that is currently in Phase III clinical trials inNorth America and Europe (Wright, T. M., Drugs of Today (2006), 42(5):291-298). This product is developed by Neurochem Inc. (Laval, QC,Canada) and it is believed to act by reducing the deposition and/or loadof amyloid in the brain through its binding to soluble AB peptide. Forincreasing the therapeutic effectiveness of 3APS, it would be desirableto increase bioavailability, stability and/or crossing the blood brainbarrier of 3APS. These and other needs can be satisfied by thedisclosure herein of a prodrug form of 3-amino-1-propanesulfonic acid(3APS), pharmaceutical compositions and uses thereof to treat variousmedical disorders.

Previous metabolic stability studies had demonstrated that there was noin vitro metabolism of 3APS. Those studies include: 3APS metabolicstability in pooled human hepatocytes, human, rat and dog livermicrosomes, human intestinal microflora, pooled human liver cytosol, andhuman arylamine N-acetyltransferase (See Examples 4 and 5).

SUMMARY OF THE INVENTION

Surprisingly, it has now been found that 3APS is metabolized both invitro and in vivo. Indeed, as described in more detail hereinafter,recent in vivo studies indicate extensive metabolism, particularlyfirst-pass and/or systemic metabolism of 3APS. Three potentialmetabolites were identified from at least one type of biologicalspecies: 2-carboxyethanesulfonic acid, 3-hydroxy-1-propanesulfonic acidand 3-acetylamino-1-propanesulfonic acid. Further studies demonstratedthat 2-carboxyethanesulfonic acid was the only major metabolite of 3APSin mice, rats, dogs and humans.

Without wishing to be bound by theory, it is hypothesized thatmetabolism of 3APS is mainly caused by a transaminase and/or monoamineoxidase that generates 2-carboxyethanesulfonic acid as the mainmetabolite and 3-hydroxy-1-propanesulfonic acid as a minor metabolite.N-acetyl-3-aminopropanesulfonic acid is another possible minormetabolite and it is believed to be produced by an enzyme thatacetylates 3APS. These hypotheses are supported by in vitro experiments(see, for example, Example 5) showing that the conversion of 3APS to2-carboxyethanesulfonic acid in primary neuron culture media wassignificantly inhibited by vigabatrin, a classic GABA transaminaseinhibitor. Nialamide, a monoamine oxidase inhibitor, also reduced theformation of 2-carboxyethanesulfonic acid (from 3APS) but to a lesserextent.

Accordingly, an aspect of the invention concerns compounds andcompositions that can deliver 3APS by minimizing the metabolism, e.g.,first-pass metabolism, associated with that drug, and more particularlycompounds that would block or protect the amino group of 3APS such thatit avoids metabolism, e.g., by transaminases and/or monoamine oxidases.

The invention includes methods, compounds, compositions and vehicles fordelivering in a subject, preferably a human subject,3-amino-1-propanesulfonic acid, or salts thereof.3-Amino-1-propanesulfonic acid (also named 3APS, Tramiprosate,Alzhemed™) has the structure:

According to an aspect, the present invention relates to compounds orcompositions that will yield or generate 3APS after administered in asubject. In one embodiment, the compound that will yield or generate3APS is an amino acid prodrug of 3APS. In another embodiment, thecompound that will yield or generate 3APS is a carbamate prodrug of3APS. In another embodiment, the compound that will yield or generate3APS is an amide prodrug of 3APS. In another embodiment, the compoundthat will yield or generate 3APS is a carbohydrate-derived prodrug of3APS. In another embodiment, the compound that will yield or generate3APS is a N-hydroxy prodrug. In another embodiment, the compound thatwill yield or generate 3APS is a cyclic double-protected prodrug. Infurther embodiment, the compound that yields or generates 3APS is a 3APSpolymer (e.g. a molecule composed of two or more molecules of 3APSlinked together). In further embodiment, the compound that yields orgenerates 3APS is a gemini dimer of 3APS. In certain embodiments, theamino acid prodrugs of 3APS that are capable of yielding or generating,either in vitro or in vivo, 3APS have one of the general or specificformulae or structures disclosed herein. The present inventionencompasses these compounds, pharmaceutical compositions containingthese compounds, and methods employing such compounds or compositions inthe treatment of various medical disorders such as Alzheimer's disease.

The present invention also relates to pharmaceutical compositionscomprising a compound of the present invention.

The present invention further relates to a method for increasing thetherapeutic effectiveness of 3APS comprising administering to a subject,preferably a human subject, an effective amount of a prodrug of thepresent invention.

The present invention also provides processes for converting compoundsof the invention to 3APS. The conversion and/or generation of 3APSinvolves contacting any of the compounds of the invention, e.g., withblood, plasma and/or brain cells. The conversion can occur in vitro orin vivo. The conversion may also occur in the presence of enzymescapable of cleaving amine bonds, such as peptidases, or other enzymesappropriate for other structures herein, including those found in theblood, plasma and/or brain.

The invention also provides the use of a compound according to theinvention for the manufacture of a medicament. The invention alsoprovides the use of a compound of the invention for the treatment orprevention of Alzheimer's disease, mild cognitive impairment, Down'ssyndrome, Hereditary Cerebral Hemorrhage with Amyloidosis of theDutch-Type, cerebral amyloid angiopathy, other degenerative dementias,dementias of mixed vascular and degenerative origin, dementia associatedwith Parkinson's disease, dementia associated with progressivesupranuclear palsy, dementia associated with cortical basaldegeneration, or diffuse Lewy body type of Alzheimer's disease. Theinvention also provides methods for the treatment or prevention of theaforementioned diseases comprising administration of a therapeuticallyeffective amount of a compound of the invention or a compositioncomprising the same, to a subject, preferably a human subject, in needthereof. More preferably, the disease is Alzheimer's disease.Accordingly, a related aspect of the invention relates to the preventionand/or treatment of Alzheimer's disease in a human subject byadministering an effective amount of a compound or composition of thepresent invention to a human subject in need thereof.

In a further embodiment the invention includes administration of 3APSvia or under the mucous membranes, the nose (intranasally), mouth, oreye, e.g., by nasal spray, chewing gum, or eye drops, via the ear, e.g.,by eardrops, by the use of an implant, rectally, e.g., by a suppositoryor enema, vaginally, e.g., by a cream or lotion, or by the respiratorysystem, e.g., by inhalation, intranasally or intratracheally.

The invention in further aspects includes the administration ofcompounds of the invention via any mode and/or vehicle, including allmodes and/or vehicles disclosed herein, e.g., the administration of theprodrugs of 3APS via the nose, mucous membranes, transdermally, via apatch, etc.

This invention in various aspects relates to the following numberedaspects:

Aspect 1. A compound of the Formula I:B-L-A  (I)whereinB is a pharmacokinetic modulating moiety, which is optionally alsobonded to A directly or indirectly through a further linking group L;A is a 3-amino-1-propanesulfonic acid moiety (i.e., 3APS bound to L-B),andL is a cleavable linkage for covalently and dissociably coupling B to A(preferably and typically via the NH₂ group), or is absent, whereby Lcan be a direct bond or additional chemical structure providing acleavable linkage,or a pharmaceutically acceptable salt or solvate thereof.

Aspect 2. The compound according to aspect 1, wherein

L is a linkage that when metabolized or hydrolyzed either in vitro or invivo produces 3APS, and/or

B is a moiety that increases the therapeutic bio-distribution of 3APSupon administration of the compound of formula I to a human subject.

Aspect 3. The compound according to aspect 1, wherein B is a3-amino-1-propanesulfonic acid moiety.

Aspect 4. A compound according to aspect 1, wherein

B is an amino acid or a peptide, and

L is a hydrolyzable linkage.

Aspect 5. A compound according to aspect 1, which is a compound offormula (I), (I-A), (I-C), (I-D), (I-E), (I-P), (I-P2), (II), (III),(IV), (V), (VI), (VII), (VIII), (IX), (X), (XI), (XII), (XII-A) or(XIII), which are set forth hereinafter, or a pharmaceuticallyacceptable salt thereof.

Aspect 6. A pharmaceutical composition comprising a compound of aspect 1and a pharmaceutically acceptable vehicle.

Aspect 7. A method for treating or preventing Alzheimer's disease, mildcognitive impairment Down's syndrome, Hereditary Cerebral Hemorrhagewith Amyloidosis of the Dutch-Type, cerebral amyloid angiopathy, adegenerative dementia, a dementia of mixed vascular and degenerativeorigin, dementia associated with Parkinson's disease, dementiaassociated with progressive supranuclear palsy, dementia associated withcortical basal degeneration, or diffuse Lewy body type of Alzheimer'sdisease comprising administering a therapeutically effective amount of acompound of aspect 1 to a human subject in need thereof.

Aspect 8. A process for converting a compound of aspect 1 to 3APScomprising contacting said compound with an enzyme which metabolizessaid compound to 3APS in vitro or in vivo.

Aspect 9. A process according to aspect 8, comprising contacting saidcompound with plasma, blood and/or brain cells.

Aspect 10. A method for increasing the therapeutic bio-distribution of3APS in a human subject, comprising lessening metabolism of 3APS, e.g.,first pass metabolism, which occurs when 3APS is administered to a humansubject.

Aspect 11. A method for reducing side effects of 3APS in a human subject(e.g., reducing or preventing gastrointestinal intolerance), comprisinglessening metabolism of 3APS, e.g., first pass metabolism, which occurswhen 3APS is administered to a human subject.

Aspect 12. A method according to aspect 10, wherein 3APS is administeredin the form of a prodrug of 3APS which yields or generates 3APS afterbeing administered to said human subject.

Aspect 13. A method according to aspect 10, wherein the prodrug is acompound of the Formula I:B-L-A  (I)whereinB is a pharmacokinetic modulating moiety, which is optionally alsobonded to A directly or indirectly through a further linking group L;A is a 3-amino-1-propanesulfonic acid moiety (i.e., 3APS bound to L-B),andL is a cleavable linkage for covalently and dissociably coupling B to A(preferably and typically via the NH₂ group), or is absent, whereby Lcan be a direct bond or additional chemical structure providing acleavable linkage,or a pharmaceutically acceptable salt or solvate thereof.

Aspect 14. A method according to aspect 10, wherein SAPS is administeredthrough the respiratory system, intratracheally, intranasally, via orunder a mucous membrane, via the ear, rectally, or vaginally, or by animplant, spray, nasal spray, chewing gum, eye drop, eardrop,suppository, enema, or vaginal cream or lotion.

Aspect 15. The method of aspect 10, wherein the bioavailability of 3APS,AUC of 3APS, brain levels of 3APS, CSF levels of 3APS, C_(max) of 3APS,T_(max) of 3APS, and/or bio-absorption of 3APS is increased.

Aspect 16. A method according to aspect 10, wherein Alzheimer's diseaseis treated or prevented.

Aspect 17. A method according to aspect 10, wherein the effectivetherapeutic level of 3APS in a selected human tissue is increased.

Aspect 18. A method according to aspect 17, which increases the level of3APS in the brain of said human subject.

Aspect 19. A method according to aspect 10, which increases thetherapeutic effectiveness of 3APS.

Aspect 20. A method according to aspect 10, which lessens the first passmetabolism of 3APS.

Aspect 21. A method according to aspect 10, which reduces the sideeffects of 3APS.

Aspect 22. A method according to aspect 10, wherein the oral AUC of 3APSis increased by at least 20%.

Aspect 23. A method for increasing the therapeutic bio-distribution of3APS in a human subject, comprising administering 3APS in the form of aprodrug or in the form of a gemini dimer of 3APS.

Aspect 24. A method for increasing the therapeutic bio-distribution of3APS in a human subject, comprising administering 3APS non-orally ornon-enterally.

Aspect 25. A method according to aspect 10, wherein 3APS is deliveredusing a route (transdermally, S.C., intranasally, etc.) or vehicle(patch, implant, spray, formulation, etc.) which minimizes hepaticfirst-pass metabolism of 3APS.

Aspect 26. A compound according to aspect 1, wherein said cleavablelinkage is selected for yielding or generating 3APS or a derivative of3APS, either in vitro or in vivo, e.g., wherein the linkage is cleavablehydrolytically or enzymatically.

Aspect 27. A compound according to aspect 1, wherein saidpharmacokinetic modulating moiety is selected for increasing thetherapeutic bio-distribution of 3APS upon administration of the compoundof formula I to a human subject.

Aspect 28. A prodrug of the Formula I:B-L-A  (I)whereinB is a pharmacokinetic modulating moiety, which is optionally alsobonded to A directly or indirectly through a further linking group L;A is a 3-amino-1-propanesulfonic acid moiety (i.e., 3APS bound to L-B),andL is a cleavable linkage for covalently and dissociably coupling B to A(preferably and typically via the NH₂ group), or is absent, whereby Lcan be a direct bond or additional chemical structure providing acleavable linkage,or a pharmaceutically acceptable salt, metabolite or solvate thereof,

wherein the metabolite of said prodrug can be 3APS and/or othermetabolites, including, but not limited to, metabolites identifiedelsewhere herein, e.g., the examples.

Additional objects, advantages and features of the present inventionwill become more apparent upon reading of the following non-restrictivedescription of preferred embodiments which are exemplary and should notbe interpreted as limiting the scope of the invention.

I. Definitions

All technical and scientific terms used herein have the same meaning ascommonly understood by one ordinary skilled in the art to which theinvention pertains. For convenience, the meaning of certain terms andphrases used herein are provided below.

To the extent the definitions of terms in the publications, patents, andpatent applications incorporated herein by reference are contrary to thedefinitions set forth in this specification, the definitions in thisspecification control. The section headings used herein are fororganizational purposes only, and are not to be construed as limitingthe subject matter disclosed.

It should be noted that, the singular forms “a”, “an”, and “the” includeplural referents unless the content clearly dictates otherwise. Thus,for example, reference to a composition containing “a compound” includesa mixture of two or more compounds. It should also be noted that theterm “or” is generally employed in its sense including “and/or” unlessthe content clearly dictates otherwise.

The chemical structures herein are drawn according to the conventionalstandards known in the art. Thus, where an atom, such as a carbon atom,as drawn appears to have an unsatisfied valency, then that valency isassumed to be satisfied by a hydrogen atom even though that hydrogenatom is not necessarily explicitly drawn. Hydrogen atoms should beinferred to be part of the compound.

The symbol “—” in general represents a bond between two atoms in thechain. Thus CH₃—O—CH₂—CH(R_(i))—CH₃ represents a2-substituted-1-methoxypropane compound. In addition, the symbol “—”represents the point of attachment of the substituent to a compound.Thus for example aryl(C₁-C₆)-alkyl indicates an arylalkyl group, such asbenzyl, attached to the compound at the alkyl moiety.

Where multiple substituents are indicated as being attached to astructure, it is to be understood that the substituents can be the sameor different. Thus for example “R_(m) optionally substituted with 1, 2or 3 R_(q) groups” indicates that R_(m) is substituted with 1, 2, or 3R_(q) groups where the R_(q) groups can be the same or different.

As used herein, the term “Compounds of the present invention” andequivalent expressions refers to compounds mentioned herein as beinguseful for at least one purpose of the invention, e.g., thoseencompassed by structural Formulae such as (I), (I-A), (I-C), (I-D),(I-E), (I-P), (I-P2), (II), (III), (IV), (V), (VI), (VII), (VIII), (IX),(X), (XI), (XII), (XII-A) and (XIII), and includes specific compoundsmentioned herein such as A1 to A35, C1 to C26, B1 to B14, H1 to H4, G1to G11, S1 to S14 and D1 to D8, etc., as well as their pharmaceuticallyacceptable salts and solvates. Embodiments herein may exclude one ormore of the compounds of the invention. Compounds may be identifiedeither by their chemical structure and/or chemical name. When thechemical structure and chemical name conflict, the chemical structure isdeterminative of the identity of the compound. The compounds describedherein may contain one or more chiral centers and/or double bonds andtherefore, may exist as stereoisomers, such as double-bond isomers(i.e., geometric isomers), enantiomers, or diastereomers. Accordingly,the chemical structures disclosed herein encompass all possibleenantiomers and stereoisomers of the illustrated compounds including thestereoisomerically pure form (e.g., geometrically pure, enantiomericallypure, or diastereomerically pure) and enantiomeric and stereoisomericmixtures. Enantiomeric and stereoisomeric mixtures can be resolved intotheir component enantiomers or stereoisomers using separation techniquesor chiral synthesis techniques well known to the skilled artisan, e.g.,chiral chromatography (such as chiral HPLC), immunoassay techniques, orthe use of covalently (such as Mosher's esters) and non-covalently (suchas chiral salts) bound chiral reagents to respectively form adiastereomeric mixture which can be separated by conventional methods,such as chromatography, distillation, crystallization or sublimation,the chiral salt or ester is then exchanged or cleaved by conventionalmeans, to recover the desired isomers. The compounds may also exist inseveral tautomeric forms including the enol form, the keto form, andmixtures thereof. Accordingly, the chemical structures depicted hereinencompass all possible tautomeric forms of the illustrated compounds.The disclosed compounds also include isotopically labeled compoundswhere one or more atoms have an atomic mass different from the atomicmass most abundantly found in nature. Examples of isotopes that may beincorporated into the compounds of the present invention include, butare not limited to, ²H (D), ³H (T), ¹¹C, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O, ¹⁷O, etc.Compounds may exist in unsolvated forms as well as solvated forms,including hydrated forms. In general, compounds may be hydrated orsolvated. Certain compounds may exist in multiple crystalline oramorphous forms. In general, all physical forms are equivalent for theuses contemplated herein and are intended to be within the scope of thepresent invention. Further, when partial structures of the compounds areillustrated, brackets or equivalents indicate the point of attachment ofthe partial structure to the rest of the molecule.

The term “prodrug” and equivalent expressions refer to agents which canbe converted in vitro or in vivo directly or indirectly to an activeform (see, e.g., R. B. Silverman, 1992, “The Organic Chemistry of DrugDesign and Drug Action,” Academic Press, Chap. 8; Bundgaard, Hans;Editor. Neth. (1985), “Design of Prodrugs”. 360 pp. Elsevier, Amsterdam;Stella, V.; Borchardt, R.; Hageman, M.; Oliyai, R.; Maag, H.; Tilley, J.(Eds.) (2007), “Prodrugs: Challenges and Rewards, XVIII, 1470 p.Springer). Prodrugs can be used to alter the biodistribution (e.g., toallow agents which would not typically enter the reactive site of theprotease) or the pharmacokinetics for a particular agent. A wide varietyof groups have been used to modify compounds to form prodrugs, forexample, esters, ethers, phosphates, etc. When the prodrug isadministered to a subject, the group is cleaved, enzymatically ornon-enzymatically, reductively, oxidatively, or hydrolytically, orotherwise to reveal the active form. As used herein, “prodrug” includespharmaceutically acceptable salts thereof, or pharmaceuticallyacceptable solvates as well as crystalline forms of any of theforegoing. Prodrugs are frequently, although not necessarily,pharmacologically inactive until converted to the parent drug.

The term “gemini dimer” and equivalent expressions refer to a syntheticcompound comprising at least two moieties of the same agent or drugcoupled together. For background on gemini dimers, see: Hammell D C,Hamad M, Vaddi H K, Crooks P A, Stinchcomb A L. A duplex “Gemini”prodrug of naltrexone for transdermal delivery. J Control Release. 2004.97(2):283-90. In preferred embodiment, the gemini dimers of theinvention are made of two linked SAPS molecules that may be converted invitro or in vivo directly or indirectly to release at least one,preferably two, pharmaceutically active 3APS molecules.

The term “carbamate” refers to an oxycarbonyl residue (—OC(O)—) linkedto an amino group to form a group comprising a (—OC(O)N(or NH)—) radicalThe carbamate group can be secondary (NH) or tertiary (N). This term isfurther defined in Section II-B(a).

The term “amide” refers to an organic compound containing a carbonyl(—C(O)—) attached to an amine group to form a group comprising theradical (—C(O)N(or NH)—). The amide group can be secondary (NH) ortertiary (N). This term is further defined in Section II-A. The term“non-amino acid amide” refers to an amide group where the carbonyl(—C(O)—) does not form part of an amino acid residue. This term isfurther defined in Section II-B(b).

The term “carbohydrate-derived” refers to compounds where the groupattached to, for example, 3APS, is an organic group that is or isderived from a polyhydroxy aldehyde, polyhydroxy ketone, or a polyol,can change to such group on simple chemical transformations, such ashydrolysis, oxidation, or reduction. These groups include, for example,sugars, starches, celluloses, and gums. This term is further defined inSection II-C. The term “N-hydroxy-derived” refers to compoundscontaining a hydroxy or hydroxy-derived group (e.g. alkoxy, benzyloxy,phenoxy, acyloxy, and the like) to form an (RO—N(or NH)—). This term isfurther defined in Section II-D(a).

The term “cyclic double-protected” refers to compounds wherein aprotecting group in linked to both the amine and the sulfonic acid of3APS. This term is further defined in Section II-D(b).

The term “ester” refers to compounds that can be represented by theformula RCOOR (carboxylic ester) or the formula RSO₃R′ (sulfonateester)′, where the group R can be, for example 3APS or the3-aminopropane part thereof, and the group R′ can be another organicgroup. These compounds are usually respectively formed by the reactionbetween a carboxylic or a sulfonic acid and an alcohol usually with theelimination of water.

The term “amino acid” generally refers to an organic compound comprisingboth a carboxylic acid group and an amine group. The term “amino acid”includes both “natural” and “unnatural” or “non-natural” amino acids.Additionally, the term amino acid includes O-alkylated or N-alkylatedamino acids, as well as amino acids having nitrogen or oxygen-containingside chains (such as Lys, Orn, or Ser) in which the nitrogen or oxygenatom has been acylated or alkylated. Amino acids may be pure L or Disomers or mixtures of L and D isomers, including racemic mixtures. Ingeneral, amino acids are represented by the residue of Formula V.

The term “natural amino acid” and equivalent expressions refer toL-amino acids commonly found in naturally occurring proteins. Examplesof natural amino acids include, without limitation, alanine (Ala),cystein (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine(Phe), glycine (Gly), histidine (His), isoleucine (Ile), lysine (Lys),leucine (Leu), methionine (Met), asparagine (Asp), proline (Pro),glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine(Val), tryptophan (Trp), tyrosine (Tyr), β-alanine ((3-ALA), andγ-aminobutyric acid (GABA).

The term “unnatural amino acid” refers to any derivative of a naturalamino acid including D forms, and α- and β-amino acid derivatives. Theterms “unnatural amino acid” and “non-natural amino acid” are usedinterchangeably herein and are meant to include the same moieties. It isnoted that certain amino acids, e.g., hydroxyproline, that areclassified as a non-natural amino acid herein, may be found in naturewithin a certain organism or a particular protein. Amino acids with manydifferent protecting groups appropriate for immediate use in the solidphase synthesis of peptides are commercially available. In addition tothe twenty most common naturally occurring amino acids, the followingexamples of non-natural amino acids and amino acid derivatives may beused according to the invention (common abbreviations in parentheses):2-aminoadipic acid (Aad), 3-aminoadipic acid (β-Aad), 2-aminobutyricacid (2-Abu), α,β-dehydro-2-aminobutyric acid (8-AU),1-aminocyclopropane-1-carboxylic acid (ACPC), aminoisobutyric acid(Aib), 3-aminoisobutyric acid (β-Aib), 2-amino-thiazoline-4-carboxylicacid, 5-aminovaleric acid (5-Ava), 6-aminohexanoic acid (6-Ahx),2-aminoheptanoic acid (Ahe), 8-aminooctanoic acid (8-Aoc),11-aminoundecanoic acid (11-Aun), 12-aminododecanoic acid (12-Ado),2-aminobenzoic acid (2-Abz), 3-aminobenzoic acid (3-Abz), 4-aminobenzoicacid (4-Abz), 4-amino-3-hydroxy-6-methylheptanoic acid (Statine, Sta),aminooxyacetic acid (Aoa), 2-aminotetraline-2-carboxylic acid (ATC),4-amino-5-cyclohexyl-3-hydroxypentanoic acid (ACHPA),para-aminophenylalanine (4-NH₂-Phe), 2-aminopimelic acid (Apm),biphenylalanine (Bip), para-bromophenylalanine (4-Br-Phe),ortho-chlorophenylalanine (2-Cl-Phe), meta-chlorophenylalanine(3-Cl-Phe), para-chlorophenylalanine (4-Cl-Phe), meta-chlorotyrosine(3-Cl-Tyr), para-benzoylphenylalanine (Bpa), tert-butylglycine (TLG),cyclohexylalanine (Cha), cyclohexylglycine (Chg), desmosine (Des),2,2-diaminopimelic acid (Dpm), 2,3-diaminopropionic acid (Dpr),2,4-diaminobutyric acid (Dbu), 3,4-dichlorophenylalanine (3,4-Cl₂-Phe),3,4-diflurorphenylalanine (3,4-F₂-Phe), 3,5-diiodotyrosine (3,5-I₂-Tyr),N-ethylglycine (EtGly), N-ethylasparagine (EtAsn),ortho-fluorophenylalanine (2-F-Phe), meta-fluorophenylalanine (3-F-Phe),para-fluorophenylalanine (4-F-Phe), meta-fluorotyrosine (3-F-Tyr),homoserine (Hse), homophenylalanine (Hfe), homotyrosine (Htyr),hydroxylysine (Hyl), allo-hydroxylysine (aHyl), 5-hydroxytryptophan(5-OH-Trp), 3- or 4-hydroxyproline (3- or 4-Hyp), para-iodophenylalanine(4-I-Phe), 3-iodotyrosine (3-I-Tyr), indoline-2-carboxylic acid (Idc),isodesmosine (Ide), allo-isoleucine (a-Ile), isonipecotic acid (Inp),N-methylisoleucine (Melle), N-methyllysine (MeLys), meta-methyltyrosine(3-Me-Tyr), N-methylvaline (MeVal), 1-naphthylalanine (1-Nal),2-naphthylalanine (2-Nal), para-nitrophenylalanine (4-NO₂-Phe),3-nitrotyrosine (3-NO₂-Tyr), norleucine (Nle), norvaline (Nva),ornithine (Orn), ortho-phosphotyrosine (H₂PO₃-Tyr),octahydroindole-2-carboxylic acid (Oic), penicillamine (Pen),pentafluorophenylalanine (F₅-Phe), phenylglycine (Phg), pipecolic acid(Pip), propargylglycine (Pra), pyroglutamic acid (PGLU), sarcosine(Sar), tetrahydroisoquinoline-3-carboxylic acid (Tic), thienylalanine,and thiazolidine-4-carboxylic acid (thioproline, Th).

As used herein, the term “acyclic” refers to an organic moiety withoutring system.

The term “aliphatic group” includes organic moieties characterized bystraight or branched-chains, typically having between 1 and 15 carbonatoms. Aliphatic groups include non cyclic alkyl groups, alkenyl groups,and alkynyl groups.

As used herein, the term “alkyl” refers to saturated hydrocarbons havingfrom one to twelve carbon atoms, including linear, branched, and cyclicalkyl groups. Examples of alkyl groups include, without limitation,methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,decyl, isopropyl, tert-butyl, sec-butyl, isobutyl, cyclopropyl,cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. The termalkyl includes both unsubstituted alkyl groups and substituted alkylgroups. The term “C₁-C_(n)alkyl”, wherein n is an integer from 2 to 12,refers to an alkyl group having from 1 to the indicated “n” number ofcarbon atoms.

As used herein, the term “alkenyl” refers to unsaturated hydrocarbonshaving from two to twelve carbon atoms, including linear, branched, andcyclic non aromatic alkenyl groups, and comprising between one to sixcarbon-carbon double bond. Examples of alkenyl groups include, withoutlimitation, vinyl, allyl, 1-propen-2-yl, 1-buten-3-yl, 1-buten-4-yl,2-buten-4-yl, 1-penten-5-yl, 1,3-pentadien-5-yl, cyclopentenyl,cyclohexenyl, ethylcyclopentenyl, ethylcylohexenyl, and the like. Theterm alkenyl includes both unsubstituted alkenyl groups and substitutedalkenyl groups. The term “C₂-C_(n)alkenyl”, wherein n is an integer from3 to 12, refers to an alkenyl group having from 2 to the indicated “n”number of carbon atoms.

As used herein, the term “alkynyl” refers to unsaturated hydrocarbonshaving from two to twelve carbon atoms, including linear, branched, andcyclic non aromatic alkynyl groups, and comprising between one to sixcarbon-carbon triple bond. Examples of alkynyl groups include, withoutlimitation, ethynyl, 1-propyn-3-yl, 1-butyn-4-yl, 2-butyn-4-yl,1-pentyn-5-yl, 1,3-pentadiyn-5-yl, and the like. The term alkynylincludes both unsubstituted alkynyl groups and substituted alkynylgroups. The term “C₂-C_(n)alkynyl”, wherein n is an integer from 3 to12, refers to an alkynyl group having from 2 to the indicated “n” numberof carbon atoms.

Unless the number of carbons is otherwise specified, “lower” as in“lower aliphatic,” “lower alkyl,” “lower alkenyl,” and “lower alkylnyl”,as used herein means that the moiety has at least one (two for alkenyland alkynyl) and equal or less than 6 carbon atoms.

The terms “cycloalkyl”, “alicyclic”, “carbocyclic” and equivalentexpressions refer to a group comprising a saturated or partiallyunsaturated carbocyclic ring in a single, Spiro (sharing one atom), orfused (sharing at least one bond) carbocyclic ring system having fromthree to fifteen ring members. Examples of cycloalkyl groups include,without limitation, cyclopropyl, cyclobutyl, cyclopentyl,cyclopenten-1-yl, cyclopenten-2-yl, cyclopenten-3-yl, cyclohexyl,cyclohexen-1-yl, cyclohexen-2-yl, cyclohexen-3-yl, cycloheptyl,bicyclo[4,3,0]nonanyl, norbornyl, and the like. The term cycloalkylincludes both unsubstituted cycloalkyl groups and substituted cycloalkylgroups. The term “C_(e)-C_(n)cycloalkyl”, wherein n is an integer from 4to 15, refers to a cycloalkyl group having from 3 to the indicated “n”number of carbon atoms in the ring structure. Unless the number ofcarbons is otherwise specified, “lower cycloalkyl” groups as hereinused, have at least 3 and equal or less than 8 carbon atoms in theirring structure.

The term “heterocycloalkyl” and equivalent expressions refer to a groupcomprising a saturated or partially unsaturated carbocyclic ring in asingle, spiro (sharing one atom), or fused (sharing at least one bond)carbocyclic ring system having from three to fifteen ring members,including one to six heteroatoms (e.g. N, O, S, P) or groups containingsuch heteroatoms (e.g. NH, NR_(x) (R_(x) is alkyl, acyl, aryl,heteroaryl or cycloalkyl), PO₂, SO, SO₂, and the like). Heterocycloalkylgroups may be C-attached or heteroatom-attached (e.g. via a nitrogenatom) where such is possible. Examples of heterocycloalkyl groupsinclude, without limitation, pyrrolidino, tetrahydrofuranyl,tetrahydrodithienyl, tetrahydropyranyl, tetrahydrothiopyranyl,piperidino, morpholino, thiomorpholino, thioxanyl, piperazinyl,azetidinyl, oxetanyl, thietanyl, homopiperidinyl, oxepanyl, thiepanyl,oxazepinyl, diazepinyl, thiazepinyl, 1,2,3,6-tetrahydropyridinyl,2-pyrrolinyl, 3-pyrrolinyl, indolinyl, 2H-pyranyl, 4H-pyranyl, dioxanyl,1,3-dioxolanyl, pyrazolinyl, dithianyl, dithiolanyl, dihydropyranyl,dihydrothienyl, dihydrofuranyl, pyrazolidinyl, imidazolinyl,imidazolidinyl, 3-azabicyclo[3,1,0]hexanyl, 3-azabicyclo[4,1,0]heptanyl,3H-indolyl, quinolizinyl, and sugars, and the like. The termheterocycloalkyl includes both unsubstituted heterocycloalkyl groups andsubstituted heterocycloalkyl groups. The term“C₃-C_(n)heterocycloalkyl”, wherein n is an integer from 4 to 15, refersto a heterocycloalkyl group having from 3 to the indicated “n” number ofatoms in the ring structure, including at least one hetero group or atomas defined above. Unless the number of carbons is otherwise specified,“lower heterocycloalkyl” groups as herein used, have at least 3 andequal or less than 8 carbon atoms in their ring structure.

The terms “aryl” and “aryl ring” refer to aromatic groups having“4n+2”π(pi) electrons, wherein n is an integer from 1 to 3, in aconjugated monocyclic or polycyclic system (fused or not) and having sixto fourteen ring atoms. A polycyclic ring system includes at least onearomatic ring. Aryl may be directly attached, or connected via aC₁-C₃alkyl group (also referred to as arylalkyl or aralkyl). Examples ofaryl groups include, without limitation, phenyl, benzyl, phenetyl,1-phenylethyl, tolyl, naphthyl, biphenyl, terphenyl, indenyl,benzocyclooctenyl, benzocycloheptenyl, azulenyl, acenaphthylenyl,fluorenyl, phenanthernyl, anthracenyl, and the like. The term arylincludes both unsubstituted aryl groups and substituted aryl groups. Theterm “C₆-C_(n)aryl”, wherein n is an integer from 6 to 15, refers to anaryl group having from 6 to the indicated “n” number of atoms in thering structure, including at least one hetero group or atom as definedabove.

The terms “heteroaryl” and “heteroaryl ring” refer to an aromatic groupshaving “4n+2”π(pi) electrons, wherein n is an integer from 1 to 3, in aconjugated monocyclic or polycyclic system (fused or not) and havingfive to fourteen ring members, including one to six heteroatoms (e.g. N,O, S) or groups containing such heteroatoms (e.g. NH, NR_(x) (R_(x) isalkyl, acyl, aryl, heteroaryl or cycloalkyl), SO, and the like). Apolycyclic ring system includes at least one heteroaromatic ring.Heteroaryls may be directly attached, or connected via a C₁-C₃alkylgroup (also referred to as heteroarylalkyl or heteroaralkyl). Heteroarylgroups may be C-attached or heteroatom-attached (e.g. via a nitrogenatom), where such is possible. Examples of heteroaryl groups include,without limitation, pyridyl, imidazolyl, pyrimidinyl, pyrazolyl,triazolyl, tetrazolyl, furyl, thienyl; isooxazolyl, thiazolyl, oxazolyl,isothiazolyl, pyrrollyl, quinolinyl, isoquinolinyl, indolyl, isoindolyl,chromenyl, isochromenyl, benzimidazolyl, benzofuranyl, cinnolinyl,indazolyl, indolizinyl, phthalazinyl, pyridazinyl, pyrazinyl, triazinyl,isoindolyl, pteridinyl, purinyl, oxadiazolyl, thiadiazolyl, furazanyl,benzofurazanyl, benzothiophenyl, benzothienyl, benzothiazolyl,benzoxazolyl, quinazolinyl, quinolizinyl, quinolonyl, isoquinolonyl,quinoxalinyl, naphthyridinyl, furopyridinyl, carbazolyl,phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl,phenothiazinyl, phenoxazinyl, dibenzofurnayl, and the like. The termheteroaryl includes both unsubstituted heteroaryl groups and substitutedheteroaryl groups. The term “C₅-C_(n)heteroaryl”, wherein n is aninteger from 6 to 15, refers to an heteroaryl group having from 5 to theindicated “n” number of atoms in the ring structure, including at leastone hetero group or atom as defined above.

The terms “heterocycle” or “heterocyclic” include heterocycloalkyl andheteroaryl groups. Examples of heterocycles include, without limitation,acridinyl, azocinyl, benzimidazolyl, benzofuranyl, benzothiofuranyl,benzothiophenyl, benzoxazolyl, benzthiazolyl, benztriazolyl,benztetrazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazolinyl,carbazolyl, 4αH-carbazolyl, carbolinyl, chromanyl, chromenyl,cinnolinyl, decahydroquinolinyl, 2H,6H-1,5,2-dithiazinyl,dihydrofuro[2,3-b]tetrahydrofuran, furanyl, furazanyl, imidazolidinyl,imidazolinyl, imidazolyl, 1H-indazolyl, indolenyl, indolinyl,indolizinyl, indolyl, 3H-indolyl, isobenzofuranyl, isochromanyl,isoindazolyl, isoindolinyl, isoindolyl, isoquinolinyl, isothiazolyl,isoxazolyl, methylenedioxyphenyl, morpholinyl, naphthyridinyl,octahydroisoquinolinyl, oxadiazolyl, 1,2,3-oxadiazolyl,1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, oxazolidinyl,oxazolyl, oxazolidinyl, pyrimidinyl, phenanthridinyl, phenanthrolinyl,phenazinyl, phenothiazinyl, phenoxathiinyl, phenoxazinyl, phthalazinyl,piperazinyl, piperidinyl, piperidonyl, 4-piperidonyl, piperonyl,pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolidinyl, pyrazolinyl,pyrazolyl, pyridazinyl, pyridooxazole, pyridoimidazole, pyridothiazole,pyridinyl, pyridyl, pyrimidinyl, pyrrolidinyl, pyrrolinyl, 2H-pyrrolyl,pyrrolyl, quinazolinyl, quinolinyl, 4H-quinolizinyl, quinoxalinyl,quinuclidinyl, tetrahydrofuranyl, tetrahydroisoquinolinyl,tetrahydroquinolinyl, tetrazolyl, 6H-1,2,5-thiadiazinyl,1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl,1,3,4-thiadiazolyl, thianthrenyl, thiazolyl, thienyl, thienothiazolyl,thienooxazolyl, thienoimidazolyl, thiophenyl, triazinyl,1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,5-triazolyl, 1,3,4-triazolyl,xanthenyl, and the like. The term heterocycle includes bothunsubstituted heterocyclic groups and substituted heterocyclic groups.

The term “amine” or “amino,” as used herein, refers to an unsubstitutedor substituted moiety of the formula —NR^(a)R^(b), in which R^(a) andR^(b) are each independently hydrogen, alkyl, aryl, or heterocyclyl, orR^(a) and R^(b), taken together with the nitrogen atom to which they areattached, form a heterocyclic ring. The term amino includes compounds ormoieties in which a nitrogen atom is covalently bonded to at least onecarbon or heteroatom. Thus, the terms “alkylamino” and “dialkylamino” asused herein means an amine group having respectively one and at leasttwo C₁-C₆alkyl groups attached thereto. The term “arylamino” and“diarylamino” include groups wherein the nitrogen is bound to at leastone or two aryl groups, respectively. The term “amide” or“aminocarbonyl” includes compounds or moieties which contain a nitrogenatom which is bound to the carbon of a carbonyl or a thiocarbonyl group.The term acylamino refers to an amino group directly attached to an acylgroup as defined herein.

The term “nitro” means —NO₂; the terms “halo” and “halogen” refer tobromine, chlorine, fluorine or iodine substituents; the term “thiol”,“thio”, or “mercapto” means SH; and the term “hydroxyl” or “hydroxy”means —OH. The term “alkylthio” refers to an alkyl group, having asulfhydryl group attached thereto. Suitable alkylthio groups includegroups having 1 to about 12 carbon atoms, preferably from 1 to about 6carbon atoms. The term “alkylcarboxyl” as used herein means an alkylgroup having a carboxyl group attached thereto.

The term “alkoxy” or “lower alkoxy” as used herein means an alkyl grouphaving an oxygen atom attached thereto. Representative alkoxy groupsinclude groups having 1 to about 6 carbon atoms, e.g., methoxy, ethoxy,propoxy, tert-butoxy and the like. Examples of alkoxy groups includemethoxy, ethoxy, isopropyloxy, propoxy, butoxy, pentoxy, fluoromethoxy,difluoromethoxy, trifluoromethoxy, chloromethoxy, dichloromethoxy,trichloromethoxy groups and the like. The term alkoxy includes bothunsubstituted or substituted alkoxy groups, etc., as well asperhalogenated alkyloxy groups.

The term “carbonyl” or “carboxy” includes compounds and moieties whichcontain a carbon connected with a double bond to an oxygen atom.Examples of moieties which contain a carbonyl include aldehydes,ketones, carboxylic acids, amides, esters, anhydrides, etc.

The term “acyl” refers to a carbonyl group that is attached through itscarbon atom to a hydrogen (i.e., formyl), an aliphatic group(C₁-C₆alkyl, C₁-C₆alkenyl, C₁-C₆alkynyl, e.g. acetyl), a cycloalkylgroup (C₃-C₈cycloalkyl), a heterocyclic group (C₃-C₈heterocycloalkyl andC₅-C₆heteroaryl), an aromatic group (C₆aryl, e.g., benzoyl), and thelike. Acyl groups may be unsubstituted or substituted acyl groups (e.g.salicyloyl).

It will be understood that “substitution” or “substituted with” includesthe implicit proviso that such substitution is in accordance with thepermitted valence of the substituted atom and the substituent, and thatthe substitution results in a stable compound, e.g., which does notspontaneously undergo transformation such as by rearrangement,cyclization, elimination, etc. As used herein, the term “substituted” ismeant to include all permissible substituents of organic compounds. In abroad aspect, the permissible substituents include acyclic and cyclic,branched and unbranched, carbocyclic and heterocyclic, aromatic andnonaromatic substituents of organic compounds. The permissiblesubstituents can be one or more. The term “substituted”, when inassociation with any of the foregoing groups refers to a groupsubstituted at one or more position with substituents such as acyl,amino (including simple amino, mono and dialkylamino, mono anddiarylamino, and alkylarylamino), acylamino (including carbamoyl, andureido), alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy,alkoxycarbonyl, carboxy, carboxylate, aminocarbonyl, mono anddialkylaminocarbonyl, cyano, azido, halogen, hydroxyl, nitro,trifluoromethyl, thio, alkylthio, arylthio, alkylthiocarbonyl,thiocarboxylate, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl,heterocycloalkyl, aryl, heteroaryl, lower alkoxy, aryloxy,aryloxycarbonyloxy, benzyloxy, benzyl, sulfinyl, alkylsulfinyl,sulfonyl, sulfate, sulfonate, sulfonamide, phosphate, phosphonato,phosphinato, oxo, guanidine, imino, formyl and the like. Any of theabove substituents can be further substituted if permissible, e.g. ifthe group contains an alkyl group, an aryl group, or other.

The term “solvate” refers to a physical association of a compound ofthis invention with one or more solvent molecules, whether organic orinorganic. This physical association includes hydrogen bonding. Incertain instances, the solvate will be capable of isolation, for examplewhen one or more solvent molecules are incorporated in the crystallattice of the crystalline solid. “Solvate” encompasses bothsolution-phase and isolable solvates. Exemplary solvates includehydrates, ethanolates, methanolates, hemiethanolates, and the like.

A “pharmaceutically acceptable salt” of a compound means a salt of acompound that is pharmaceutically acceptable. Desirable are salts of acompound that retain or improve the biological effectiveness andproperties of the free acids and bases of the parent compound as definedherein or that takes advantage of an intrinsically basic, acidic orcharged functionality on the molecule and that is not biologically orotherwise undesirable. Example of pharmaceutically acceptable salts arealso described, for example, in Berge et al., “Pharmaceutical Salts”, J.Pharm. Sci. 66, 1-19 (1977). Such salts include:

(1) acid addition salts, formed on a basic or positively chargedfunctionality, by the addition of inorganic acids such as hydrochloricacid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfamic acid,nitric acid, phosphoric acid, carbonate forming agents, and the like; orformed with organic acids such as acetic acid, propionic acid, lacticacid, oxalic, glycolic acid, pivalic acid, t-butylacetic acid,β-hydroxybutyric acid, valeric acid, hexanoic acid,cyclopentanepropionic acid, pyruvic acid, malonic acid, succinic acid,malic acid, maleic acid, fumaric acid, tartaric acid, citric acid,benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelicacid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonicacid, 2-hydroxyethanesulfonic acid, cyclohexylaminosulfonic acid,benzenesulfonic acid, sulfanilic acid, 4-chlorobenzenesulfonic acid,2-napthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid,3-phenyl propionic acid, lauryl sulphonic acid, lauryl sulfuric acid,oleic acid, palmitic acid, stearic acid, lauric acid, embonic (pamoic)acid, palmoic acid, pantothenic acid, lactobionic acid, alginic acid,galactaric acid, galacturonic acid, gluconic acid, glucoheptonic acid,glutamic acid, naphthoic acid, hydroxynapthoic acid, salicylic acid,ascorbic acid, stearic acid, muconic acid, and the like;

(2) base addition salts, formed when an acidic proton present in theparent compound either is replaced by a metal ion, including, an alkalimetal ion (e.g. lithium, sodium, potassium), an alkaline earth ion (e.g.magnesium, calcium, barium), or other metal ions such as aluminum, zinc,iron and the like; or coordinates with an organic base such as ammonia,ethylamine, diethylamine, ethylenediamine, N,N′-dibenzylethylenediamine,ethanolamine, diethanolamine, triethanolamine, tromethamine,N-methylglucamine, piperazine, chloroprocain, procain, choline, lysineand the like.

Pharmaceutically acceptable salts may be synthesized from the parentagent that contains a basic or acidic moiety, by conventional chemicalmethods. Generally, such salts are prepared by reacting the free acid orbase forms of these agents with a stoichiometric amount of theappropriate base or acid in water or in an organic solvent, or in amixture of the two. Salts may be prepared in situ, during the finalisolation or purification of the agent or by separately reacting apurified compound of the invention in its free acid or base form withthe desired corresponding base or acid, and isolating the salt thusformed. The term “pharmaceutically acceptable salts” also includezwitterionic compounds containing a cationic group covalently bonded toan anionic group, as they are “internal salts”.

All acid, salt, base, and other ionic and non-ionic forms of thecompounds described are included as compounds of the invention. Forexample, if a compound is shown as an acid herein, the salt forms of thecompound are also included. Likewise, if a compound is shown as a salt,the acid and/or basic forms are also included.

“Abeta”, “Aβ”, or “β-amyloid”, is defined as any peptide resulting frombeta-secretase mediated cleavage of Beta Amyloid Precursor Protein(APP), including for examples peptides of 37, 38, 39, 40, 41, 42, and 43amino acids, and extending from the beta-secretase cleavage site toamino acids 37, 38, 39, 40, 41, 42, or 43. It also includes It alsoincludes N-terminal truncated species of above peptides, such as thepyroglutamic forms pE3-40, pE3-42, pE3-43, pE11-42, pE11-43 and thelike. For convenience of nomenclature, “Aβ₁₋₄₂”, may be referred toherein as “Aβ(1-42)” or simply as “Aβ₄₂” (and likewise for any otheramyloid peptides discussed herein). As used herein, the terms “Abeta”,“Aβ”, “β-amyloid”, “amyloid-β” are synonymous referring collectively totruncated and non-truncated peptide species of the sequence between β-and γ-cleavage sites of APP.

The term “amyloid-β disease” or “amyloid-β related disease” may be usedfor mild cognitive impairment; vascular dementia; early Alzheimer'sdisease; Alzheimer's disease, including sporadic (non-hereditary)Alzheimer's disease and familial (hereditary) Alzheimer's disease;age-related cognitive decline; cerebral amyloid angiopathy (“CAA”);hereditary cerebral hemorrhage; senile dementia; Down's syndrome;inclusion body myositis (“IBM”); or age-related macular degeneration(“ARMD”), Mild cognitive impairment (“MCI”), Cerebral amyloid angiopathy(“CAA”), age-related macular degeneration (ARMD).

“AUC” is the area under a curve representing the concentration of acompound in a biological sample of a subject as a function of timefollowing administration of the compound to the subject. Examples ofbiological samples include biological fluids such as plasma and blood,or organ homogenates such as brain or liver homogenates. The AUC can bedetermined by measuring the concentration of a compound in a biologicalsample such as the plasma, blood or brain homogenate using methods suchas liquid chromatography-tandem mass spectrometry (LC/MS/MS), at varioustime intervals, and calculating the area under theconcentration-versus-time curve. Suitable methods for calculating theAUC from a drug concentration-versus-time curve are well known in theart. As relevant to the disclosure here, an AUC for 3APS can bedetermined by measuring the concentration of 3APS in the plasma, bloodor brain homogenate of a subject following oral administration of acompound of Formulae (I), (I-A), (I-C), (I-D), (I-E), (I-P), (I-P2),(II), (III), (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI), (XII) or(XII-A), to the subject. Unless noted otherwise herein; AUC meansAUC_(0-∞), as further defined in Example 4.

“Bioavailability” refers to the rate and amount of a drug that reachesthe systemic circulation of a subject following administration of thedrug or prodrug thereof to the patient and can be determined byevaluating, for example, the plasma or blood concentration-versus-timeprofile for the drug. Parameters useful in characterizing a plasma orblood concentration-versus-time curve include the area under the curve(AUC), the time to peak concentration (T_(max)), and the maximum drugconcentration (C_(max)). Bioavailability is often expressed as F (%)referring to the ratio in percentage of the AUC of the compound for aspecific mode of administration (e.g. orally) over AUC of the compoundafter an IV administration.

“Bioequivalence” refers to equivalence of the rate and extent ofabsorption of a drug after administration of equal doses of the drug orprodrug to a patient. As used herein, two plasma or blood concentrationprofiles are bioequivalent if the 90% confidence interval for the ratioof the mean response of the two profiles is within the limits of 0.8 and1.25. The mean response includes at least one of the characteristicparameters of a profile such as C_(max), T_(max), and AUC.

“C_(max)” is the maximum concentration of a drug in the biologicalsample of a subject following administration of a dose of the drug orprodrug to the subject.

“T_(max)” is the time to the maximum concentration (C_(max)) of a drugin the biological sample of a subject following administration of a doseof the drug or prodrug to the subject.

As used herein the term “effective amount” refers to the amount or doseof the compound, upon single or multiple dose administration to thepatient, which provides the desired effect in the patient underdiagnosis or treatment. An effective amount can be readily determined bythe attending diagnostician, as one skilled in the art, by the use ofknown techniques and by observing results obtained under analogouscircumstances. In determining the effective amount or dose of compoundadministered, a number of factors are considered by the attendingdiagnostician, including, but not limited to: the size, age, and generalhealth of the subject; the specific disease involved; the degree of orinvolvement or the severity of the disease; the response of theindividual subject; the particular compound administered; the mode ofadministration; the bioavailability characteristics of the preparationadministered; the dose regimen selected; the use of concomitantmedication; and other relevant circumstances.

As used herein the term “therapeutic bio-distribution of 3APS” refers toone or more pharmacokinetic parameters of SAPS which affect 3APStherapeutic activity. Examples of such pharmacokinetic (PK) parametersinclude but are not limited to: bioavailability of 3APS, AUC of 3APS,brain levels of 3APS, CSF levels of 3APS, C_(max) of 3APS, T_(max) of3APS, and/or bio-absorption of 3APS, etc.

As used herein the terms “increased (or like terms, e.g., increasing,increase in, etc.) therapeutic effectiveness of 3APS” and “enhanced (orlike terms, e.g., enhancing, enhancement, etc.) therapeuticeffectiveness of 3APS” refer to an increased effectiveness of 3APS asmeasured, e.g., by one or more parameters listed under “therapeuticbio-distribution of 3APS” above, e.g., by 5%, 10%, 20%, 30%, 40%, 50%,60%, 70%, 80%, 90%, 95%, 99%, 125%, etc., or even more, e.g., 2, or 4fold, or even more when administered to a subject, e.g., animal orhuman, which increase is with respect to the same equivalent molar doseof 3APS administered orally in water solution. Preferably such increasesare achieved also with respect to 3APS administered orally in theformulation of Table 3 of U.S. Ser. No. 11/103,656, filed on Apr. 12,2005. Effectiveness can also be as measured, for example, by effect oncharacteristics of a disease such as Alzheimer's disease, e.g., by thereduction of plaques or Aβ load in the brain, or by an improvement inselected manifestations of the disease, e.g., memory loss, cognition,reasoning, judgment, orientation, etc. See U.S. Ser. No. 11/103,656,filed on Apr. 12, 2005, for details on how to measure effects oncharacteristics of such diseases.

The term “lessening metabolism of 3APS” (or related terms such asreduction, less, lowering, reducing, lowered, etc) refers to decreasingthe degree or amount of first-pass metabolism in the GI tract or liverof 3APS (by administering it to a subject non-orally or in particularoral formulations or in the form of a prodrug) by e.g., 5%, 10%, 20%,30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or even 100%, whichdecrease is with respect to the degree or amount of metabolism of SAPSthat occurs when the same equivalent molar dose of 3APS is administeredorally in water solution. Preferably such % decreases are achieved alsowith respect to 3APS administered orally in the formulation of Table 3of U.S. Ser. No. 11/103,656, filed on Apr. 12, 2005.

The term “reduction of side effects of 3APS” refers to decreasing theamount of or severity of one or more side effects of 3APS by, e.g., 5%,10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or 99.9%, or even100%, which decrease is with respect to the amount of or severity of aside effect of 3APS that is exhibited when the same equivalent molardose of 3APS is administered orally in water solution. Preferably such %decreases are achieved also with respect to 3APS administered orally inthe formulations of Table 3 of U.S. Ser. No. 11/103,656, filed on Apr.12, 2005.

More generally, the terms lessening etc., increasing etc., refer incontext herein to the percentage changes, e.g., by 5%, 10%, 20%, 30%,40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, 125%, etc., or even more, e.g.,2, or 4 fold, or even more.

All of the pharmacokinetic data in U.S. Ser. No. 11/103,656, filed onApr. 12, 2005, are incorporated herein by reference, including the datafor example 1 and of Table 3, for example, for forming a comparativebasis for the effects achieved by the present inventions.

When referring to “3APS” being produced (e.g., released from aformulation or prodrug), all forms of 3APS are included, e.g., solvatesthereof, ionically dissociated forms thereof, charged forms thereof,etc.

“Pharmaceutically acceptable” refers to drugs, medicaments, inertingredients etc., which the term describes, suitable for use in contactwith the tissues of humans and lower animals without undue toxicity,incompatibility, instability, irritation, allergic response, and thelike, commensurate with a reasonable benefit/risk ratio. It preferablyrefers to a compound or composition that is approved or approvable by aregulatory agency of the Federal or state government or listed in theU.S. Pharmacopoeia or other generally recognized pharmacopoeia for usein animals and more particularly in humans.

“Pharmaceutically acceptable vehicle” refers to a diluent, adjuvant,excipient, or carrier with which a compound is administered.

“Pharmaceutical composition” refers to at least one compound and atleast one pharmaceutically acceptable vehicle, with which the compoundis administered to a patient.

“Preventing” or “prevention” is intended to refer at least the reductionof likelihood of the risk of (or susceptibility to) acquiring a diseaseor disorder (i.e., causing at least one of the clinical symptoms of thedisease not to develop in a patient that may be exposed to orpredisposed to the disease but does not yet experience or displaysymptoms of the disease).

“Treating” or “treatment” of any disease or disorder refers, in someembodiments, to ameliorating at least one disease or disorder (i.e.,arresting or reducing the development of the disease or at least one ofthe clinical symptoms thereof). In certain embodiments “treating” or“treatment” refers to ameliorating at least one physical parameter,which may or may not be discernible by the patient. In certainembodiments, “treating” or “treatment” refers to inhibiting the diseaseor disorder, either physically, (e.g., stabilization of a discerniblesymptom), physiologically, (e.g., stabilization of a physicalparameter), or both. In certain embodiments, “treating” or “treatment”refers to delaying the onset of the disease or disorder. The term“treating” refers to any indicia of success in the treatment oramelioration of an injury, pathology or condition, including anyobjective or subjective parameter such as abatement; remission;diminishing of symptoms or making the injury, pathology or conditionmore tolerable to the subject; slowing in the rate of degeneration ordecline; making the final point of degeneration less debilitating;improving a subject's physical or mental well-being; or, in somesituations, preventing the onset of dementia. The treatment oramelioration of symptoms can be based on objective or subjectiveparameters; including the results of a physical examination, apsychiatric evaluation, or a cognition test such as CDR, MMSE, DAD,ADAS-Cog, or another test known in the art. For example, the methods ofthe invention successfully treat a subject's dementia by slowing therate of or lessening the extent of cognitive decline.

“Therapeutically effective amount” means the amount of compound that,when administered to a patient for treating or preventing a disease, issufficient to effect such treatment or prevention of the disease. The“therapeutically effective amount” will vary depending on the compound,the disease and its severity, and the age, weight, etc., of the patienthaving the disease to be treated or prevented.

Reference will now be made in detail to certain embodiments of compoundsand, methods. The disclosed embodiments are not intended to be limitingof the invention.

In a further aspect the invention includes the administration of 3APSthat is not via a transdermal patch, or not by topical administration ina composition, e.g., lotions, creams, solutions, gels or solids or notby subcutaneous, intravenous or intraperitoneal injection, or notintraspinally, or intracerebrally.

II. Compounds of the Invention

The present invention relates to methods, compounds and compositions fordelivering in a subject, preferably a human subject,3-amino-1-propanesulfonic acid, or salts thereof, also referred hereinas 3APS. The invention encompasses compounds that will yield or generate3APS, either in vitro or in vivo.

In a preferred embodiment, compounds of the invention include prodrugsthat will yield or generate 3APS once administered in a human. Withoutwishing to be bound by theory, in some aspects the prodrugs according toinvention comprise a “pharmacokinetic modulating moiety,” e.g., B,below, covalently but dissociably linked to 3APS that, e.g., by alinkage, L, below, which will be cleaved once in the blood, plasma orother specific tissue (e.g. brain), thereby releasing 3APS.

Thus, in one aspect, the invention relates to a compound of the FormulaI:B-L-A  (I)as well as pharmaceutically acceptable salts, metabolites, and solvatesthereof, where:B is a pharmacokinetic modulating moiety, which is optionally alsobonded to A directly or indirectly thought a further linking group L;A is 3-amino-1-propanesulfonic acid moiety (i.e., 3APS bound to L-B);andL is a cleavable linkage for covalently and dissociably coupling B to A(preferably and typically via the NH₂ group), or is absent, whereby Lcan be a direct bond or additional chemical structure providing acleavable linkage.

Suitable pharmacokinetic modulating moieties (e.g. B) moieties includeamino acid or peptide moieties, carbamate moieties, non-amino-acid amidemoieties, carbohydrate-derived moieties and analogs such asinositol-derived moieties, N-hydroxy and derivatives thereof (e.g.,where the H in OH is replaced by an OH protecting group). B can alsocomprise a cyclic double protected 3APS molecule and precursors (e.g.,where a moiety connects NH₂ and SO₃H of 3APS, e.g., sulfinic acids,thiols, sulfides, disulfides, etc.), and combinations thereof. Moregenerally B moieties include N-protecting groups. B can also be themolecule 3APS itself (see gemini dimers).

Suitable linkages L will be any which are cleaved as described herein,e.g., by enzymes mentioned herein or others in blood, plasma and orbrain cells, in vitro or in vivo. Linkages will generally comprise abond which is known to be so cleavable such as but not limited to, apeptide, amide, ester, sulfide, disulfide, carboxamate, urea, —N—O—,etc. bond, and others as demonstrated for example in the structuresdisclosed herein, all of which are in general applicable as linkages, L,in compounds in general. Actual cleavability of the linker can beassessed in vitro and/or in vivo by using hydrolytic-, enzymatic- (e.g.peptidase, esterase) or metabolic-based tests and assays well known inthe art. International PCT application WO 91/14434, publishedapplications US 2005/0096317, US 2006/0046967 and provisionalapplication U.S. 60/xxx,xxx filed concurrently herewith, are allincorporated herein by reference since they describe a variety oflinkers that may be useful according to the present invention.

In another aspect, the invention relates to Formula I-A (and salts,esters and solvates thereof)

wherein,

R^(x) and R^(y) are independently selected from hydrogen and aprotecting group, wherein R^(x) and R^(y) are not both hydrogen; and

L¹ and L² are each a cleavable linkage; wherein when R^(x) is H, L¹ isabsent, and when R^(y) is H, then L² is absent.

The term “protecting group” refers to a group inhibiting and reducingmetabolism of the amino group of 3APS. Examples of protecting groupsinclude, without limitation, an amino acid residue, a carbamate, anon-amino acid amide, a carbohydrate-derived residue, aN-hydroxy-derived residue, a cyclic double protecting group, and thelike.

According to preferred embodiments, the compounds of the inventionexhibit numerous advantageous properties. In one embodiment, thecompound is a prodrug which bypasses first-pass metabolism by the liverand/or the digestive tract (e.g. gut, stomach, or intestine) that isassociated with administration of 3APS, per se, thereby increasingbio-distribution and/or bioavailability of 3APS as compared to anadministration of a molar equivalent of 3APS. Bypassing hepaticfirst-pass metabolism modifies, improves or increases pharmacokineticparameters of 3APS such as the AUC, the C_(max) and/or T_(max) of 3APS.In one embodiment, the compound is a prodrug which exhibits an increasedabsorption by the gastrointestinal tract, compared to the administrationa molar equivalent of 3APS per se. In one embodiment, the compound is aprodrug which provides a slow release of 3APS over time. In anotherembodiment, the compound is a prodrug which increases brain levels of3APS when compared to the administration a molar equivalent of 3APS perse. In another embodiment, the compound is a prodrug which lessenscommon side effects associated with the administration of 3APS per se.For instance, in a preferred embodiment, the prodrug exhibits a bettergastrointestinal tolerability than 3APS.

In preferred embodiments the compounds and/or compositions of theinvention achieve one or more of the following benefits: (1) reducingthe molar dose of 3APS administered to a patient (e.g. due to a improvedabsorption when compared to 3APS or due to a reduction in the first-passmetabolism of 3APS); (2) avoiding common side effects such asgastrointestinal irritation associated with an oral administration of3APS; (3) improving penetration of 3APS across the BBB; (4) reducing theside effects associated with 3APS (e.g. by lessening gastrointestinalproblems or by increasing the relative amount of 3APS reaching thebrain; (5) increasing concentration or levels of 3APS in desired tissuesor fluids (e.g. brain, CSF). Other benefits will be apparent to thoseskilled in the art.

The invention pertains to both salt forms and acid/base forms of thecompounds of the invention. For example, the invention pertains not onlyto the particular salt forms of compounds shown herein as salts, butalso the invention includes other pharmaceutically acceptable salts, andthe acid and/or base form of the compound. The invention also pertainsto salt forms of compounds shown herein. Compounds of the invention arealso shown in Table 1, Table 2, Table 3, Table 4 and Table 4B below.

The compounds of the present invention may exhibit polymorphism.Polymorphs of compounds according to this invention may be prepared bycrystallization under different conditions. For example, using differentsolvents or different solvent mixtures for recrystallization;crystallization at different temperatures; various modes of coolingranging from very fast to very slow cooling during crystallization.Polymorphs may also be obtained by heating or melting a prodrug followedby gradual or fast cooling. The presence of polymorphs may be determinedby solid probe NMR spectroscopy, IR spectroscopy, differential scanningcalorimetry, powder X-ray diffraction or other such techniques.

The compounds of the present invention may also exist in the form of asolvate, for example, hydrate, ethanolate, n-proponalate,iso-propanolate, 1-butanolate, 2-butanolate and solvates of otherphysiologically acceptable solvents, such as the Class 3 solventsdescribed in the International Conference on Harmonization (ICH),Guidance for Industry, Q3C Impurities: Residual Solvents (1997). Thepresent invention includes each solvate and mixtures thereof.

The amino acid or peptidic moiety, the carbamate moiety, the non-aminoacid amide moiety, the carbohydrate-derived moiety and analogs such asinositol-derived, the N-hydroxy moiety and derivatives, or any otherpharmacokinetic modulating moiety of the prodrugs, including cyclicdouble protected 3APS and precursors (e.g. sulfinic acids, thiol,sulfide, disulfide, etc), and combinations thereof, according to theinvention may be cleaved prior to absorption by the gastrointestinaltract (e.g., within the stomach or intestinal lumen) and/or afterabsorption by the gastrointestinal tract (e.g., in intestinal tissue,blood, liver, or other suitable tissue of a mammal). In certainembodiments, 3APS remains covalently attached to the pharmacokineticmodulating moiety during transit across the intestinal mucosal barrierto provide protection from presystemic metabolism. In certainembodiments, pharmacokinetic modulating moieties according to theinvention are essentially not metabolized to the corresponding 3APSwithin cells of the intestine or liver (e.g. enterocytes, hepatocytes),but generates the parent 3APS molecule once within the systemiccirculation. In certain embodiments, at least some of the prodrugadministered generates the corresponding 3APS only once in the brain,i.e. after it has passed the blood brain barrier (BBB). Cleavage of thepharmacokinetic modulating moiety of prodrugs according to the inventionafter absorption by the gastrointestinal tract may allow these prodrugsto be absorbed into the systemic circulation either by active transport,passive diffusion, or by a combination of both active and passiveprocesses. Accordingly, in certain embodiments, a pharmaceuticalcomposition, formulation, or dosage form of the present invention iscapable of maintaining a therapeutically effective concentration of 3APSin the plasma or blood of a patient for a time period of at least about1 hour, for at least 2 hours, for at least 3 hours, 4 hours, for atleast about 8 hours, for a period of at least about 12 hours, at leastabout 16 hours, at least about 20 hours, and in certain embodiments forat least about 24 hours after the pharmaceutical composition,formulation, or dosage form comprising a corresponding compoundaccording to the invention and a pharmaceutically acceptable vehicle isorally administered to the patient. In certain embodiments, apharmaceutical composition, formulation, or dosage form of the presentinvention is capable of improving the T_(max) of 3APS by at least 2fold, or by at least 3, 4, 5, 6, 7, 8, 9 or 10 fold or more.

The pharmacokinetic modulating moiety of certain of the compoundsaccording to the invention may be cleaved either chemically and/orenzymatically. One or more enzymes present in the stomach, intestinallumen, intestinal tissue, blood, liver, brain, or any other suitabletissue of a mammal may enzymatically cleave the amino acid or peptidicmoiety of the compound. If the pharmacokinetic modulating moiety iscleaved after absorption by the gastrointestinal tract, certain of thecompounds according to the invention may have the opportunity to beabsorbed into the systemic circulation from the large intestine. Incertain embodiments, the pharmacokinetic modulating moiety is cleavedafter absorption by the gastrointestinal tract or after crossing theBBB.

Although theory of operation is discussed herein, for specific compoundstructures, including all generic structural formulas and specific namesand formulas of compounds, the invention is not limited by any suchtheories unless specifically stated otherwise. Thus, all uses of allnovel compounds are encompassed by the invention, irrespective ofmechanism or theory of operation.

II-A. Amino Acid Prodrugs

In a preferred embodiment, the compounds of the invention are aminoacids prodrugs that will yield or generate 3APS once administered in ahuman. Preferred prodrugs are composed of an amino acid residue linkedto the amine group of 3APS via an amide bond. The amino acid residue maybe cleaved in vivo by enzymes such as peptidases, or by any othermechanisms, to liberate the amine group of 3APS.

More particularly, an aspect of the invention relates to a compound ofFormula (II), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein AA is a natural or unnatural amino acid residue or a peptidecomprising 2, 3 or more natural or unnatural amino acid residues.

Other aspects of the invention relate to compounds of Formula (III) andto a pharmaceutically acceptable salt or solvate thereof:

wherein:

aa¹ is a natural or unnatural amino acid residue;

aa² and aa³ are each independently a natural or unnatural amino acidresidue or absent.

Further aspects of the invention relate to compounds of Formula (IV) andto pharmaceutically acceptable salts, esters or solvates thereof:

wherein:

aa¹ is a natural or unnatural amino acid residue;

aa² is a natural or unnatural amino acid residue, or is absent.

Yet further aspects of the invention relate to compounds of Formula (V),and to pharmaceutically acceptable salts, esters or solvates thereof:

wherein aa¹ is a natural or unnatural amino acid residue.

The invention further relates to compounds of Formula (V-A), and topharmaceutically acceptable salts, esters or solvates thereof:

wherein aa^(x) is an amino acid residue selected from valine, proline,lysine, leucine, methionine, D-methionine, serine, alanine, D-alanine,glycine, isoleucine, histidine, aminoisobutyric acid, phenylglycine,tryptophan, tyrosine, O-benzylserine, O-benzylglutamine, andγ-aminobutyric acid.

In preferred embodiments aa^(x) is an amino acid residue selected fromvaline, lysine, methionine, serine, and O-benzylserine, or apharmaceutically acceptable salt or solvate thereof.

In one embodiment, the amino acid residue is coupled via an acid end(C-coupled). In an embodiment, the amino acid residue is a natural aminoacid residue, or a salt or ester thereof. In another embodiment, theamino acid residue is an unnatural amino acid residue, or a salt orester thereof. In yet another embodiment, the amino acid residue is nota phenylalanine, e.g., in the case where a single amino acid is attachedto the N atom, but also in any other case. In a further embodiment,natural or unnatural amino acid residues in Formula II, Formula III,Formula IV, Formula V, or Formula V-A are optionally represented byFormula (VI):

wherein:

R¹ and R² are each independently selected from the group consisting of Hand a substituted or unsubstituted group selected from C₁-C₁₂alkyl,C₂-C₁₂alkenyl, C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl, C₃-C₁₅heterocycloalkyl,C₆-C₁₅aryl, C₅-C₁₅heteroaryl, NH(C₁-C₆alkyl), N(C₁-C₆alkyl)₂, andC(O)(C₁-C₆alkyl); or R¹ and R² are taken together with the adjacentcarbon atom to form a substituted or unsubstitutedC₃-C₁₂heterocycloalkyl;

R³ is selected from the group consisting of H and a substituted orunsubstituted group selected from C₁-C₁₂alkyl, C₂-C₁₂alkenyl,C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl, C₃-C₁₅heterocycloalkyl, C₆-C₁₅aryl,C₅-C₁₅heteroaryl, C(O)(C₁-C₆alkyl), and C(O)(C₆-C₁₀aryl); or R³ is abond between two amino acid residues, when at least two amino acidresidues are present;

R⁴ is selected from the group consisting of H and a substituted orunsubstituted group selected from C₁-C₆alkyl, C₂-C₆alkenyl,C₂-C₆alkynyl; or R¹ and R⁴ are taken together with the adjacent carbonand nitrogen atoms to form a C₃-C₁₀heterocycloalkyl; and

n is 1, 2 or 3, or a higher number.

In one embodiment, the compound of the invention comprises an amino acidresidue of Formula VI, wherein R² is H and all other groups are aspreviously disclosed. In another embodiment, the compound of theinvention comprises an amino acid residue of Formula VI, wherein R² andR³ are each H and all other groups are as previously disclosed. Inanother embodiment, the compound of the invention comprises an aminoacid residue of Formula VI, wherein when R² and R³ are each H, then R¹is not an aryl-substituted C₁alkyl. In another embodiment, the compoundof the invention comprises an amino acid residue of Formula VI, whereinwhen R² and R³ are each H, then R¹ is not a —CH₂aryl group. In anotherembodiment, the compound of the invention comprises an amino acidresidue of Formula VI, wherein when R² is H and R³ is H or a bond, thenR¹ is not a —CH₂phenyl group. In another embodiment, the inventionprovides compounds of Formula V, provided that aa¹ is not aphenylalanine. In another embodiment, the invention provides compoundsof Formula IV, provided that aa¹ and aa² are not both D-phenylalanine.In another embodiment, the invention provides compounds of Formula IV,provided that aa¹ and aa² are not both L-phenylalanine. In anotherembodiment, the invention provides compounds of Formula IV, providedthat when one of aa¹ and aa² is D-phenylalanine, then the other is notD-phenylalanine or D-tyrosine. In yet another embodiment, the inventionprovides compounds of Formula IV, provided that when one of aa¹ and aa²is L-phenylalanine, then the other is not D-phenylalanine or L orD-tyrosine.

TABLE 1 Exemplary amino acid prodrugs according to the invention IDStructure A1

A2

A3

A4

A5

A6

A7

A8

A9

A10

A11

A12

A13

A14

A15

A16

A17

A18

A19

A20

A21

A22

A23

A24

A25

A26

A27

A28

A29

A30

A31

A32

A33

A34

A35

Preferred amino acid prodrugs according to the invention are CompoundsA2, A4, A6, A7 and A18 (as described above), and pharmaceuticallyacceptable salts and solvates thereof.

II-B. Carbamate, Non-Amino Acid Amide and Related Prodrugs

Certain aspects of the invention relate to a compound of Formula (VII),and to pharmaceutically acceptable salts, esters or solvates thereof:

wherein,

R⁵ is a substituted or unsubstituted group selected from C₁-C₁₂alkyl,C₂-C₁₂alkenyl, C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl, C₃-C₁₅heterocycloalkyl,C₆-C₁₅aryl, C₅-C₁₅heteroaryl, NH(C₁-C₆alkyl), N(C₁-C₆alkyl)₂, andC(O)(C₁-C₆alkyl);

R⁶ is a hydrogen or a substituted or unsubstituted group selected fromC(O)NH₂, C(O)NH(C₁-C₆alkyl), C(O)N(C₁-C₆alkyl)₂, and C(O)(C₁-C₆alkyl);or R⁵ and R⁶ are taken together with the adjacent carbon atom to form asubstituted or unsubstituted C₃-C₁₂heterocycloalkyl;

M is selected from the group consisting of oxygen, sulfur, and nitrogen(NH or N(C₁-C₆alkyl)) or is absent.

The invention pertains to both salt forms and acid/base forms of thecompounds of the invention. For example, the invention pertains not onlyto the particular salt forms of compounds shown herein as salts, butalso the invention includes other pharmaceutically acceptable salts, andthe acid and/or base form of the compound. The invention also pertainsto salt forms of compounds shown herein.

In one embodiment, the invention provides compounds of Formula VII,wherein when M is absent and R⁶ is H, then R⁵ is other than1-(4-isobutylphenyl)ethyl. In another embodiment, the invention providescompounds of Formula VII, wherein when R⁶ is H and M is NH or absent,then R⁵ is other than 1-(4-isobutylphenyl)ethyl. In another embodiment,the invention provides compounds of Formula VII, wherein when R⁶ is Hand M is NH, then R⁵ is other than benzyl, diphenylmethyl, hexyl,dodecyl, adamantyl, and t-butyl. In another embodiment, the inventionprovides compounds of Formula VII, wherein when R⁶ is H and M is NH,then R⁵ is other than hydrogen,1,4-dihydro-5,6-dimethyl-4-oxo-2-pyrimidinyl, and5-ethyloxycarbonyl-1-penthyl. In another embodiment, the inventionprovides compounds of Formula VII, wherein when M is NH and R⁵ and R⁶are taken together with the adjacent carbon atom to form a substitutedor unsubstituted C₃₋₁₂heterocycloalkyl, then the heterocycloalkyl isother than benzimidazol-2-one, tetrahydro-2,4,6-trioxo-1,3,5-triazine,2,4-dioxo-1-imidazolidine, 2,4-dioxo-(di ortetrahydro)-benzo[g]pteridine,4,10-dihydro-10-methyl-2,4-dioxopyrimido[4,5b]quinoline,2-oxo-1-imidazolidinyl, and 3,4-dihydro-2,4-dioxo-1(2H)pyrimidine. Inanother embodiment, the invention provides compounds of Formula VII,wherein when M is NH, then R⁵ and R⁶ are not taken together with theadjacent carbon atom to form a substituted or unsubstitutedC₃₋₁₂heterocycloalkyl. In another embodiment, the invention providescompounds of Formula VII, wherein when R⁶ is H and M is O, then R⁵ isother than t-butyl and benzyl. In another embodiment, the inventionprovides compounds of Formula VII, wherein when R⁶ is H and M is O, thenR⁵ is other than i-butyl and 9H-fluoren-9-ylmethyl. In anotherembodiment, the invention provides compounds of Formula VII, whereinwhen R⁶ is H and M is absent, then R⁵ is other than benzyl, phenyl,3-pyridinyl, 3-N-methylpyridinium, methyl, trifluoromethyl,pentafluoroethyl, pentafluorophenyl, and t-butyl. In another embodiment,the invention provides compounds of Formula VII, wherein when R⁶ is Hand M is absent, then R⁵ is other than n-butyl, i-butyl, n-propyl,i-propyl, vinyl, 2-propenyl, 2-(1-decenyl), 2-(1-dodecenyl),1-(8-undecenyl), octyl, decyl, undecyl, tridecyl, pentadecyl,heptadecyl, 4-(N-oxy-2,2,6,6-tetramethylpiperidinyl),5-(1,3-dihydro-1,3-dioxo-2-benzofuranyl), 4-nitrophenyl, and3-phenoxyphenyl.

a) Carbamate Prodrugs

In some preferred embodiments, the compounds of the invention arecarbamate prodrugs that will yield or generate SAPS once administered ina human. Preferred prodrugs comprise an oxycarbonyl residue (—OC(O)—)linked to the amine group of 3APS via a carbamate bond (—OC(O)—NH—). Theamine residue may be cleaved in vivo by enzymes or by any othermechanisms, including hydrolysis, to liberate the amine group of 3APS.In a preferred embodiment, the compounds of the invention are carbamateprodrugs that will yield or generate SAPS once administered in a human.

More particularly, certain aspects of the invention relate to a compoundof Formula (VIII), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein,

R⁷ is a substituted or unsubstituted group selected from C₁-C₁₂alkyl,C₂-C₁₂alkenyl, C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl, C₃-C₁₅heterocycloalkyl,C₆-C₁₅aryl, C₅-C₁₅heteroaryl, C₇-C₁₂arylalkyl, C₇-C₁₂heteroarylalkyl,and combinations thereof.

In one embodiment, the definition of R⁷ is a substituted orunsubstituted 1-(alkylcarboxy)alkyl group. In another embodiment, R⁷ isa substituted or unsubstituted benzyl group. In another embodiment, R⁷is a substituted or unsubstituted heterocycloalkylmethylene group. Inanother embodiment, the invention provides compounds of Formula VIII,provided that R⁷ is other than t-butyl or benzyl. In another embodiment,the invention provides compounds of Formula VIII, provided that R⁷ isother than i-butyl or 9H-fluoren-9-ylmethyl.

The invention pertains to both salt forms and acid/base forms of thecompounds of the invention. For example, the invention pertains not onlyto the particular salt forms of compounds shown herein as salts, butalso the invention includes other pharmaceutically acceptable salts, andthe acid and/or base form of the compound. The invention also pertainsto salt forms of compounds shown herein. Compounds of the invention arealso shown in Table 2 below.

TABLE 2 Exemplary carbamate prodrugs according to the invention IDStructure C1

C2

C3

C4

C5

C6

C7

C8

C9

C10

C11

C12

C13

C14

C15

C16

C17

C18

C19

C20

C21

C22

C23

C24

C25

C26

b) Non-Amino Acid Amide Prodrugs

In some preferred embodiments, the compounds of the invention arenon-amino acid amide prodrugs that will yield or generate SAPS onceadministered to a human. Preferred prodrugs comprise acarbonyl-containing residue linked to the amine group of 3APS via anamide bond. The carbonyl-containing residue may be cleaved in vivo byenzymes or by any other mechanism, to liberate the amine group of 3APS.

Preferred prodrugs are composed of a carbonyl-containing residue linkedto the amine group of 3APS via an amide bond and suchcarbonyl-containing group having a nucleophile such as a carboxylic acidor alcohol, capable of internally cleaving the amide bond. The aminoacid residue may be cleaved in vivo by enzymes, or by any othermechanism, to liberate the amine group of 3APS.

More particularly, certain aspects of the invention relate to a compoundof Formula (IX), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein,

R⁸ is a substituted or unsubstituted group selected from C₁-C₁₂alkyl,C₂-C₁₂alkenyl, C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl, C₃-C₁₅heterocycloalkyl,C₆-C₁₅aryl, C₅-C₁₅heteroaryl; and

R⁹ is a hydrogen or a substituted or unsubstituted C(O)(C₁-C₆alkyl),C(O)NH₂, C(O)NH(C₁-C₆alkyl), or C(O)N(C₁-C₆alkyl)₂; or R⁸ and R⁹ aretaken together with the adjacent carbon atom to form a substituted orunsubstituted C₃-C₁₂heterocycloalkyl.

In one embodiment, R⁸ is a substituted C₁-C₁₂alkyl. In anotherembodiment, R⁸ is a C₁-C₁₂alkyl substituted with a substituent selectedfrom hydroxycarbonyl, alkoxycarbonyl, alkylcarbonyloxy, substituted orunsubstituted 2-hydroxyphenyl, substituted or unsubstituted2-alkylcarbonyloxyphenyl group or combinations thereof. In anotherembodiment, R⁸ is a substituted or unsubstituted benzyl group. In afurther embodiment, R⁸ is selected from the groups depicted in Table 3.

In one embodiment, the compound of the invention is a compound ofFormula IX, wherein R⁹ is H. In another embodiment, the compound of theinvention is a compound of Formula IX, wherein R⁸ and R⁹ are takentogether with the adjacent carbon atom to form a substituted orunsubstituted C₃-C₁₂heterocycloalkyl. In another embodiment, thecompound of the invention is a compound of Formula IX, wherein R⁸ and R⁹are taken together with the adjacent carbon atom to form a substitutedor unsubstituted phthalimide. In another embodiment, the compound of theinvention is a compound of Formula IX, wherein R⁸ and R⁹ are takentogether with the adjacent carbon atom to form a substituted orunsubstituted C₃-C₁₂heterocycloalkyl, wherein said heterocycle is otherthan phthalimide. In another embodiment, the invention providescompounds of Formula IX, wherein when R⁹ is H, then R⁸ is other thanbenzyl, phenyl, 3-pyridinyl, 3-N-methylpyridinium, methyl,trifluoromethyl, pentafluoroethyl, pentafluorophenyl, and t-butyl. Inanother embodiment, the invention provides compounds of Formula IX,wherein when R⁹ is H, then R⁸ is other than n-butyl, butyl, n-propyl,i-propyl, vinyl, 2-propenyl, 2-(1-decenyl), 2-(1-dodecenyl),1-(8-undecenyl), octyl, decyl, undecyl, tridecyl, pentadecyl,heptadecyl, 4-(N-oxy-2,2,6,6-tetramethylpiperidinyl),5-(1,3-dihydro-1,3-dioxo-2-benzofuranyl), 4-nitrophenyl, and3-phenoxyphenyl. In another embodiment, the invention provides compoundsof Formula IX, wherein R⁸ is selected from n-butyl, i-butyl, n-propyl,i-propyl, vinyl, 2-propenyl, 2-(1-decenyl), 2-(1-dodecenyl),1-(8-undecenyl), octyl, decyl, undecyl, tridecyl, pentadecyl,heptadecyl, 4-(N-oxy-2,2,6,6-tetramethylpiperidinyl),5-(1,3-dihydro-1,3-dioxo-2-benzofuranyl), 4-nitrophenyl, and3-phenoxyphenyl. In yet another embodiment, the invention provides acompound of Formula IX, wherein when R⁹ is H, then R⁸C(O) is other thana 24-oxocholan-24-yl. In yet another embodiment, the invention providesa compound of Formula IX, wherein when R⁹ is H, then R⁸C(O) is otherthan (3α,5β)-3-hydroxy-24-oxocholan-24-yl,(3α,5β,12α)-3,12-dihydroxy-24-oxocholan-24-yl,(3α,5β,7α)-3,7-dihydroxy-24-oxocholan-24-yl, or(3α,5β,7α,12α)-3,7,12-trihydroxy-24-oxocholan-24-yl. In yet anotherembodiment, the invention provides a compound of Formula IX, whereinR⁸C(O) is selected from (3α,5β)-3-hydroxy-24-oxocholan-24-yl,(3α,5β,12α)-3,12-dihydroxy-24-oxocholan-24-yl,(3α,5β,7α)-3,7-dihydroxy-24-oxocholan-24-yl, and(3α,5β,7α,12α)-3,7,12-trihydroxy-24-oxocholan-24-yl.

The invention pertains to both salt forms and acid/base forms of thecompounds of the invention. For example, the invention pertains not onlyto the particular salt forms of compounds shown herein as salts, butalso the invention includes other pharmaceutically acceptable salts, andthe acid and/or base form of the compound. The invention also pertainsto salt forms of compounds shown herein. Compounds of the invention arealso shown in Table 3 below.

TABLE 3 Exemplary non-amino acid amide prodrugs according to theinvention ID Structure B1

B2

B3

B4

B5

B6

B7

B8

B9

B10

B11

B12

B13

B14

II-C. Carbohydrate-Derived Prodrugs

In some preferred embodiments, the compounds of the invention arecarbohydrate-derived prodrugs that will yield or generate 3APS onceadministered in a human. Preferred prodrugs according to the inventiondisclosed herein comprise a carbohydrate or a polyol analog residuelinked to the amine group of 3APS via a linkage, e.g. an amide, acarbamate, a urea, or a cleavable alkyl group. In one embodiment, thecarbohydrate-derived moiety is, for example, a carbohydrate derivativesuch as hexose, pentose, a carbohydrate-derived polyol, inositol or aninositol-derived moiety, a carbohydrate-derived carboxylic acid,ascorbic acid, nucleic acid, or nucleotide. The linkage and/orcarbohydrate-derived residue may be cleaved in vivo by enzymes or by anyother mechanism, to liberate the amine group of 3APS.

More particularly, certain aspects of the invention relate to a compoundof Formula (X), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein,

R¹⁰ is a residue of a carbohydrate, a carbohydrate derivative or acarbohydrate-derived polyol, e.g., a C₅₋₆ saturated or partially orcompletely unsaturated cycloalkyl group, optionally and preferablycontaining an —O— group, which is substituted by 3 to 5 substituents,each independently selected from —OH, —OAc, —CH₂OH, —OCH₃, —CH₂OAc and═O.

L is a linking moiety or is absent, e.g., an alkyl group, which may besaturated or unsaturated, preferably a lower alkyl group, which isoptionally interrupted by one or more —O— and/or —NH— groups, and isoptionally substituted by one or more ═O, —OH, and/or —NH₂ groups.

In one embodiment, the invention provides a compound of Formula X,wherein when L is absent, then R¹⁰ is other than 2-deoxy-2-D-glucose.

The invention pertains to both salt forms and acid/base forms of thecompounds of the invention. For example, the invention pertains not onlyto the particular salt forms of compounds shown herein as salts, butalso the invention includes other pharmaceutically acceptable salts, andthe acid and/or base form of the compound. The invention also pertainsto salt forms of compounds shown herein. Compounds of the invention arealso shown in Table 4A below.

TABLE 4A Exemplary carbohydrate-derived prodrugs according to theinvention ID Structure S1

S2

S3

S4

S5

S6

S7

S8

S9

S10

S11

S12

S13

S14

S15

S16

S17

II-D. Other Prodrugs

In some preferred embodiments, the compounds of the invention areN-hydroxy prodrugs and derivatives, cyclic double-protected prodrugs,precursors of 3APS, as prodrugs that will yield or generate 3APS onceadministered in a human.

a) N-Hydroxy-Derived Prodrugs

More particularly, certain aspects of the invention relate to a compoundof Formula (XI), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein,

R¹¹ is a hydrogen or a substituted or unsubstituted group selected fromC₁-C₁₂alkyl, C₂-C₁₂alkenyl, C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl,C₆-C₁₅heterocycloalkyl, C₆-C₁₅aryl, C₅-C₁₅heteroaryl, C(O)R¹², andC(O)OR¹³; and

R¹² and R¹³ are independently selected from substituted or unsubstitutedC₁-C₁₂alkyl, C₂-C₁₂alkenyl, C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl,C₆-C₁₅heterocycloalkyl, C₆-C₁₅aryl, C₅-C₁₅heteroaryl.

In one embodiment, the invention provides compounds of Formula XI,wherein R¹¹ is other than a hydroxyl.

b) Cyclic Double-Protected Prodrugs

More particularly, certain aspects of the invention relate to a compoundof Formula (XII), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein,

D is a carbonyl, an amino acid residue, or a substituted methylenegroup; and

X is selected from O, NH, and S.

More particularly, certain aspects of the invention relate to a compoundof Formula (XII-A), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein,

R¹⁴ is a substituted or unsubstituted group selected from C₁-C₁₂alkyl,C₂-C₁₂alkenyl, C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl, C₃-C₁₅heterocycloalkyl,C₆-C₁₅aryl, C₅-C₁₅heteroaryl.

Compounds of the invention include the following compounds:

c) Imine Prodrugs

More particularly, certain aspects of the invention relate to a compoundof Formula (XIII), and to pharmaceutically acceptable salts, esters orsolvates thereof:

wherein,

R¹⁵ and R¹⁶ are independently selected from a hydrogen or a substitutedor unsubstituted group selected from C₁-C₁₂alkyl, C₂-C₁₂alkenyl,C₂-C₁₂alkynyl, C₃-C₁₅cycloalkyl, C₃-C₁₅heterocycloalkyl, C₆-C₁₅aryl, andC₅-C₁₅heteroaryl.

In one embodiment, the invention provides compounds of Formula XIII,wherein when both R¹⁵ and R¹⁶ are substituted or unsubstituted aryl,then at least one of R¹⁵ and R¹⁶ is substituted with a hydroxyl group atthe ortho position. In another embodiment, the invention providescompounds of Formula XIII, wherein when both R¹⁵ and R¹⁶ are substitutedor unsubstituted aryl, then none of R¹⁵ and R¹⁶ is substituted with ahydroxyl group at the ortho position.

Compounds of the invention include the following compounds:

In some preferred embodiments, the compounds of the invention comprise acombination of any of the prodrugs described herein in sections II-A toII-D, as prodrugs that will yield or generate SAPS once administered ina human. The invention further relates to sulfonic acid precursors ofany of the prodrugs mentioned in Sections II-A to II-D, includingsulfonate esters, sulfonamides, sulfinic acids, sulfides, disulfides andthe like.

II-E Oligomers and Gemini Dimers

In a further embodiment the compound of the Formula I may comprise twoor more 3APS molecules linked together. Therefore, another aspect of theinvention relates to polymers of 3APS, i.e., a molecule comprising, orconsisting essentially of, or consisting of two or more molecules of3APS linked together with cleavable linkage. Thus, another aspect of theinvention relates to a compound of the Formula I-P:A-(L^(x)-A)_(p)-L^(x)-A  (I-P)as well as pharmaceutically acceptable salts, esters, metabolites, andsolvates thereof, where:

A is 3-amino-1-propanesulfonic acid moiety;

L^(x) is a cleavable linkage for covalently and dissociably couplingtogether two adjacent 3APS moieties, and

p is 0, or an integer number which may vary from 1 to 5, e.g. 2, 3, 4,or 5.

Those skilled in the art will readily understand that there can be agreat number of possible variations or orientations for couplingtogether three or more SAPS moieties (the number of possibilities being2^(n-1), n being equal to 3 for a trimer (4 possibilities), n=4 fortetramer (8 possibilities), etc). Indeed, as exemplified with moredetails hereinafter with gemini dimers, such connections could be madevia the NH₂ group or the SO₃H group of the 3APS molecule. For instance,for a trimer of SAPS (i.e., 3 molecules of 3APS), there would be 4different possibilities:

1) ♦-*♦-*♦-; 2) ♦-*♦-*-♦; 3) ♦-*-♦*♦-; 4) ♦-*-♦*-♦;

the symbol “♦” representing the NH₂ group of the 3APS molecule, thesymbol “-” the SO₃H group of the 3APS molecule, and the symbol “*”representing the position of the linkage.

Alternatively, the invention relates to a compound of Formula I-P2:L^(y)(A)_(m)  (I-P2)and pharmaceutically acceptable salts, esters, and solvates thereof,where:

m is an integer from 2 to 5;

A is 3-amino-1-propanesulfonic acid moiety;

L^(y) is a multivalent carrier moiety for covalently and dissociablycoupling from two to five A moieties, either at the amino or sulfonicacid end of A.

In preferred embodiments, the compounds of the Formula I-P comprise orare

“Gemini dimers” i.e., they comprise two 3APS molecules linked togetherwith a cleavable linkage. Thus, in another aspect; the invention relatesto compounds of Formula I-C (and salts, esters and solvates thereof):

wherein, L³ is bivalent linker which connects two molecules of 3APS attheir amino groups either using the same or different linkages asdefined herein, including, but not limited to, amide linkage andcarbamate linkage.

In another aspect, the invention relates to compounds of Formula I-D(and salts, esters, and solvates thereof):

wherein, L⁴ is a bivalent linker which connects two molecules of 3APS attheir sulfonic acid groups either using the same or different linkagesas defined herein, including, but not limited to, ester linkage oranhydride linkage where X is oxygen, or sulfonamide linkage where X isnitrogen (NH, or NR), or thiosulfonate linkage where X is sulfur. P ishydrogen or a N-protecting group as defined herein.

In another aspect, the invention relates to compounds of Formula I-E(and salts, esters, and solvates thereof):

wherein, L⁵ is a bivalent linker which connects two molecules of 3APS,at amino group in one 3APS using a linkage as defined in Formula I-C,and at sulfonic acid group in the other 3APS using a linkage as definedin Formula I-D. P is hydrogen or a N-protecting group as defined herein.

In preferred embodiment, the linker L^(x), L³, L⁴, or L⁵, or the carriermoiety L^(y) are selected such that the two, three, four or five linked3APS moieties may be converted in vitro or in vivo, directly orindirectly, to release two, three, four or five pharmaceutically active3APS molecules. The capability of releasing the parent 3APS molecule(s)may be tested and, in many cases, it can be predicted. More preferably,the linker is designed to bind the 3APS molecules via their nitrogenatoms (for improved protection against first pass metabolism), but asexemplified hereinbefore, it is also possible to bind the 3APS moleculesvia the oxygen atom of their sulfonate group (e.g., through anester-type of linkage) or via their sulfur atom (e.g., sulfonamidelinked dimers). Various permutations of the above are also possible.Those skilled in the art will be capable to select proper linkers andlinkage site and test the resulting product for efficacy and forcapability of cleavage under various chemical and/or biologicalconditions. Compounds of the invention are also shown in Table 4B below.

TABLE 4B Exemplary gemini dimers according to the invention ID StructureG1

G2

G3

G4

G5

G6

G7

G8

G9

G10

G11

The invention pertains to both salt forms and acid/base forms of thecompounds of the invention. For example, the invention pertains not onlyto the particular salt forms of compounds shown herein as salts, butalso the invention includes other pharmaceutically acceptable salts, andthe acid and/or base form of the compound. The invention also pertainsto salt forms of compounds shown herein.

III. Synthesis of the Compounds of the Invention

In general, all compounds of the present invention may be prepared bythe methods illustrated in the Examples hereinafter and/or otherconventional methods, using readily available and/or conventionallypreparable starting materials, reagents and conventional synthesisprocedures. In these reactions, it is also possible to make use ofvariants which are in themselves known, but are not mentioned here.Certain novel and exemplary methods of preparing the inventive compoundsare described in the Exemplification section. Such methods are withinthe scope of this invention. Functional and structural equivalents ofthe compounds described herein and which have the same generalproperties, wherein one or more simple variations of substituents aremade which do not adversely affect the essential nature or the utilityof the compound are also included.

More particularly, the amino acid prodrugs of the present invention maybe prepared by the methods illustrated in Example 1-A hereinafter, andin general reaction schemes such as, for example, described in Schemes 1and 2, or by modifications thereof.

The carbamate prodrugs of the present invention may be prepared by themethods illustrated in Example 1-B hereinafter, or by modificationsthereof.

The non-amino acid prodrugs of the present invention may be prepared bythe methods illustrated in Example 1-C hereinafter, and in the generalreaction schemes such as, for example, the amide coupling stepsdescribed in Schemes 1 and 2, or by modifications thereof.

The carbohydrate-derived prodrugs may be prepared by the methodsillustrated in Example 1-D hereinafter, or by known coupling reactionsdepending on the linkage used (carbamate, urea, amide, and the like), orby modifications thereof.

The N-hydroxy prodrugs and their derivatives may be prepared byoxidation of the amine group, and by alkylating such N-hydroxy groupwhen desired. The procedures to accomplish these reactions are readilyavailable and known to the skilled artisan.

The cyclic double-protected prodrugs are prepared according to standardprocedures for the cyclization of such groups, depending on the D and Xgroups used.

The compounds of the present invention may be readily prepared inaccordance with the synthesis schemes and protocols described herein, asillustrated in the specific procedures provided. However, those skilledin the art will recognize that other synthetic pathways for forming thecompounds of this invention may be used, and that the following isprovided merely by way of example, and is not limiting to the presentinvention. See, e.g., “Comprehensive Organic Transformations” by R.Larock, VCH Publishers (1989). It will be further recognized thatvarious protecting and deprotecting strategies will be employed that arestandard in the art (See, e.g., “Protective Groups in Organic Synthesis”by Greene and Wuts (1991)). Those skilled in the relevant arts willrecognize that the selection of any particular protecting group (e.g.,amine, hydroxyl, thio, and carboxyl protecting groups) will depend onthe stability of the protected moiety with regards to the subsequentreaction conditions and will understand the appropriate selections.

Further illustrating the knowledge of those skilled in the art is thefollowing sampling of the extensive chemical literature: “Chemistry ofthe Amino Acids” by J. P. Greenstein and M. Winitz, John Wiley & Sons,Inc., New York (1961); “Advanced Organic Chemistry: Reactions,Mechanisms, and Structure” by J. March, 4th Edition, John Wiley & sons(1992); T. D. Ocain, et al., J. Med, Chem., 31, 2193-99 (1988); E. M.Gordon, et al., J. Med. Chem. 31, 2199-10 (1988); “Practice of PeptideSynthesis” by M. Bodansky and A. Bodanszky, Springer-Verlag, New York(1984); “Asymmetric Synthesis: Construction of Chiral Molecules UsingAmino Acids” by G. M. Coppola and H. F. Schuster, John Wiley & Sons,Inc., New York (1987); “The Chemical Synthesis of Peptides” by J. Jones,Oxford University Press, New York (1991); and “Introduction of PeptideChemistry” by P. D. Bailey, John Wiley & Sons, Inc., New York (1992).

The synthesis of compounds of the invention is preferably carried out ina solvent. Suitable solvents are liquids at ambient room temperature andpressure or remain in the liquid state under the temperature andpressure conditions used in the reaction. The choice of solvent iswithin the general skills of the skilled artisan and will depend on thereaction conditions, such, temperature, the nature of the reagents andstarting material, solubility and stability of the reagents and startingmaterial, the type of reaction, and the like. Depending on thecircumstances, solvents may be distilled or degassed. Solvents may be,for example, aliphatic hydrocarbons (e.g., hexanes, heptanes, ligroin,petroleum ether, cyclohexane, or methylcyclohexane) and halogenatedhydrocarbons (e.g., methylenechloride, chloroform, carbontetrachloride,dichloroethane, chlorobenzene, or dichlororbenzene); aromatichydrocarbons (e.g., benzene, toluene, tetrahydronaphthalene,ethylbenzene, or xylene); ethers (e.g., diglyme, methyl-tert-butylether, methyl-tert-amyl ether, ethyl-tert-butyl ether, diethylether,diisopropylether, tetrahydrofuran or methyltetrahydrofurans, dioxane,dimethoxyethane, or diethyleneglycol dimethylether); amides (e.g.,N,N-dimethylformamide, N,N-dimethylacetamide); nitriles (e.g.,acetonitrile); ketones (e.g., acetone); esters (e.g., methyl acetate orethyl acetate); alcohols (e.g., methanol, ethanol, isopropanol); waterand mixtures thereof.

“Activated esters” and equivalent expressions may be represented by theformula COX, where X is a leaving group, typical examples of whichinclude N-hydroxysulfosuccinimidyl and N-hydroxysuccinimidyl groups;aryloxy groups substituted with electron-withdrawing groups (e.g.,p-nitro, pentafluoro, pentachloro, p-cyano, or p-trifluoromethyl); andcarboxylic acids activated by a carbodiimide or other conventionalcoupling reagents to form an anhydride or mixed anhydride, e.g.,—OCOR^(a) or —OCNR^(a)NHR^(b), where R^(a) and R^(b) are independentlyC₁-C₆ alkyl, C₅-C₈ alkyl (e.g., cyclohexyl), C₁-C₆ perfluoroalkyl, orC₁-C₆ alkoxy groups. An activated ester may be formed in situ or may bean isolable reagent. The ester leaving group may be, for example,sulfosuccinimidyl esters, pentafluorothiophenol esters,sulfotetrafluorophenol, substituted or unsubstituted C₁-C₆ alkyl (suchas methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl,tert-butyl, pentyl, or hexyl), or substituted or unsubstituted C₆-C₁₄aryl or heterocyclic groups, such as 2-fluoroethyl, 2-chloroethyl,2-bromoethyl, 2,2-dibromoethyl, 2,2,2-trichloroethyl, 3-fluoropropyl,4-chlorobutyl, methoxymethyl, 1,1-dimethyl-1-methoxymethyl,ethoxymethyl, N-propoxymethyl, isopropoxymethyl, N-butoxymethyl,tert-butoxymethyl, 1-ethoxyethyl, 1-methyl-1-methoxyethyl,1-(isopropoxy)ethyl, 3-methoxypropyl-4-methoxybutyl,fluoromethoxymethyl, 2,2,2-trichloroethoxymethyl,bis(2-chloroethoxy)methyl, 3-fluoropropoxymethyl, 4-chlorobutoxyethyl,dibromomethoxyethyl, 2-chloroethoxypropyl, fluoromethoxybutyl,2-methoxyethoxymethyl, ethoxymethoxyethyl, methoxyethoxypropyl,methoxyethoxybutyl, benzyl, phenethyl, 3-phenylpropyl, 4-phenylbutyl,α-naphthylmethyl, β-naphthylmethyl, diphenylmethyl, triphenylmethyl,α-naphthyldipheylmethyl, 9-anthrylmethyl, 4-methylbenzyl,2,4,6-trimethylbenzyl, 3,4,5-trimethylbenzyl, 4-methoxybenzyl,4-methoxyphenyldiphenylmethyl, 2-nitrobenzyl, 4-nitrobenzyl,4-chlorobenzyl, 4-bromobenzyl, 4-cyanobenzyl,4-cyanobenzyldiphenylmethyl, or bis(2-nitrophenyl)methyl groups.

III. Exemplary Synthesis of Amino Acid Prodrugs According to theInvention

The following schemes are for illustration purposes and are not intendedto be limiting. The coupling of 3-amino-1-propanesulfonic acid with afirst amino acid may be generally represented by Scheme 1:

wherein R¹, R² and R⁴ are as previously disclosed, R^(z) is R³ or aprotecting group, and X is the leaving group of an activated ester.

In Scheme 1, a monoamino acid prodrug of 3-amino-1-propanesulfonic acidis produced by reacting its free amino group (or a protected sulfonateester variant) with an activated ester of the desired amino acid (whichmay be N-protected). Group C(O)X of the activated ester may be an acylhalide, mixed anhydride, succinimide ester, or may be a carboxylic acidactivated by a peptide coupling agent (e.g., carbodiimides (such as EDC(1-(3-dimethylaminopropyl)-3-diisopropylethylcarbodiimide)) and uroniums(such as HATU (O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluroniumhexafluorophosphate))), in the presence of a base (e.g., amines (such asDIPEA (N,N-diisopropylethylamine), hydroxides (such as sodiumhydroxide), carbonates (such as potassium carbonate), etc), andoptionally a catalyst (e.g. 4-(dimethylamino)pyridine (DMAP),1-hydroxybenzotriazole (HOBt)). The choice of base and catalyst willdepend mainly on the nature of the activated ester.

At this stage, protecting groups (R^(z) on amine or protecting groupspresent on heteroatoms in R¹ and R² groups) may be removed. Protectinggroups on heteroatoms other than on the amine may not be removed iffurther amino acid couplings are necessary (see Scheme 2). Protectinggroups of oxygen atoms may include benzyl and silyl ethers, acetals andesters, protecting groups of nitrogen may include carbamates andfluorene derivatives. They are cleaved by widely used procedures (see,for example, Greene and Wuts (1991), supra).

wherein R^(1′), R^(2′) and R^(4′) are defined respectively as R¹, R² andR⁴ but may or may not be the same as R¹, R² and R⁴ in the above scheme,and R¹, R², R⁴, R^(z) and X are as previously disclosed.

Scheme 2 is used to produce prodrugs comprising two or more amino acidsattached to 3APS. Coupling conditions are generally the same asdescribed for Scheme 1. Subsequent amino acids are added in the samemanner, with a deprotection of the amine group between each couplingstep. If other protecting groups are present on heteroatoms of theresidues, they may be removed during a last chemical step.

In general, after completion of the reaction, the product is isolatedfrom the reaction mixture according to standard techniques. For example,the solvent is removed by evaporation or filtration if the product issolid, optionally under reduced pressure. After the completion of thereaction, water may be added to the residue to make the aqueous layeracidic or basic and the precipitated compound filtered, although careshould be exercised when handling water-sensitive compounds. Similarly,water may be added to the reaction mixture with a hydrophobic solvent toextract the target compound. The organic layer may be washed with water,dried over anhydrous magnesium sulfate or sodium sulfate, and thesolvent is evaporated to obtain the target compound. The target compoundthus obtained may be purified, if necessary, e.g., by recrystallization,reprecipitation, chromatography, or by converting it to a salt byaddition of an acid or base.

IV. Alternate Routes and Vehicles for Delivering SAPS by Minimizing orLessening Hepatic First-Pass Metabolism

As indicated hereinbefore, an aspect of the invention concerns newroutes of administration (e.g. transdermally, subcutaneously,intranasally, etc.) and new pharmaceutical vehicles (e.g. patches,implants, spray, formulations (including for oral administration)) forlessening hepatic first-pass metabolism of 3APS.

Transdermal Drug Delivery Devices

The delivery of drugs by the transdermal route is an area of increasinginterest and offers the advantage of allowing a prolonged, steady inputof drug into the blood. Transdermal delivery of SAPS is one preferredembodiment of the invention because it could avoid hepatic first-passmetabolism that is associated with administration of 3APS, and thusincrease the therapeutic effectiveness of 3APS. Transdermal delivery mayalso help avoid the pain associated with injections, and may increasedosage compliance.

Accordingly, certain aspects of the present invention relate to a methodfor the delivery of a compound according to the invention, preferably3APS, to improve the effectiveness of the compound in the treatment ofcognitive disorders. The invention further relates to a method ofdelivering a compound according to the invention, preferably 3APS,wherein the compound may be administered in a transdermal patch.

Transdermal drug delivery devices according to the invention can bemanufactured using techniques and components well known to the skilledartisan. Transdermal drug delivery devices typically involve includes abacking layer, which may optionally be composed of a pigmented polyesterfilm, a drug reservoir, a microporous membrane that controls the rate ofdelivery of the drug from the system to the skin surface, and anadhesive formulation to attach the delivery system to a subject.Optionally, the adhesive formulation may include the drug, thusproviding a more immediate bolus of the compound upon application of thepatch to a subject.

Transdermal drug delivery devices also typically involve a carrier (suchas a liquid, gel, or solid matrix, or a pressure sensitive adhesive)into which the drug to be delivered is incorporated. The drug-containingcarrier is then placed on the skin and the drug, along with anyadjuvants and excipients, is delivered to the skin. Typically theportions of the carrier that are not in contact with the subject's skinare covered by a backing. The backing serves to protect the carrier (andthe components contained in the carrier, including the drug) from theenvironment and prevents loss of the ingredients of the drug deliverydevice to the environment. Because hydration of the stratum corneum isknown to enhance transport of certain drugs across the skin, it issometimes desirable that the backing have a relatively low moisturevapor transmission rate in order to retain moisture at the site coveredby the drug delivery device. In order to maintain the health of thecovered skin during long term wear (e.g., for periods in excess of aday) by allowing the skin to breath, it is also desirable that thebacking have relatively high permeability to oxygen. Further, as thebacking is in contact with the components of the carrier, including thedrug and any adjuvants and excipients, it is important that the backingbe stable to such components in order that the backing retains itsstructural integrity, tensile strength, and conformability to the skin.It is also desirable that the backing not absorb drug or otherexcipients from the carrier. In connection with the preparation ofcertain reservoir-type transdermal drug delivery devices, it is alsodesirable for the backing to be heat sealable at a relatively lowtemperature to itself and to a variety of other polymeric substrates.Backing materials that have found use in transdermal drug deliverydevices include metal foils, metalized plastic films, and single layeredand multilayered polymeric films (see U.S. Pat. No. 5,264,219).

Membranes useful in the construction of a transdermal patch are known inthe art and include, but are not limited to, CoTran™ membranescommercially available from 3M, such as the COTRAN™ 9701, 9702, 9705,9706, 9715, 9716, 9726, and COTRAN™ 9728 membranes. Backing useful inthe construction of a transdermal patch are known in the art andinclude, but are not limited to, backing material commercially availablefrom 3M, such as COTRAN™ and SCOTCHPAK™ backings. Likewise, liners arewell known in the art and may be obtained from a number of commercialsources. Optionally, a gelling agent may be optionally added at up to20% by volume. Gelling agents, include, but are not limited to:crosslinked acrylic acid polymers, such as the “carbomer” family ofpolymers, e.g., carboxypolyalkylenes that may be obtained commerciallyunder the tradename CARBOPOL™; hydrophilic polymers, such aspolyethylene oxides, polyoxyethylene-polyoxypropylene copolymers andpolyvinylalcohol; cellulosic polymers, such as hydroxypropyl cellulose,hydroxyethyl cellulose, hydroxypropyl methylcellulose, hydroxypropylmethylcellulose phthalate, and methyl cellulose; gums such as tragacanthand xanthan gum; sodium alginate; and gelatin.

Those skilled in the art will readily identified the proper combinationand/or concentration of backing layer, drug reservoir, membrane,carrier, backing, penetration enhancer, gelling agent, etc. Ifnecessary, one could refer to the numerous publications on the subject,including the patent literature such as EP 1 602 367, US 2005/019384, US2005/0074487 and US 2005/175680 all describing transdermal drug deliverydevices and associated. For instance, the absorption through human skinof a drug may be used to determine the feasibility of transdermaldelivery with a particular carrier or vehicle. For example, penetrationof a compound according to the invention, preferably 3APS, across humanepidermis may be measured in vitro using glass diffusion cells.Therefore, optimization of the compound's absorption is achieved by useof formulations disclosed herein and known in the art as penetrationenhancers. Additional well known tests and assays include permeabilityrate studies, absorption studies, diffusion assays, time-courseprofiling for penetration across human epidermis, irritancy studies,etc.

Clinical studies indicate that an oral dose of a 3APS of about 100and/or 150 mg bid may produce a beneficial treatment for cognitivedisorders, such as AD. Since transdermal administration of a compoundaccording to the invention, preferably 3APS, is believed to be subjectto reduced first-pass metabolism, the dosage of a 3APS may be reducedwhen administered transdermally. On the other hand, transdermaladministration could be helpful to increase the dosage of 3APS byavoiding common side effects such as gastrointestinal irritationassociated with an oral administration of that drug.

A benefit of a transdermal dosage form includes improved subjectcompliance, due to the possibility of reduced administrations. Forexample, a transdermal patch of the invention may be formulated so as toprovide one, two, three, four, five, six or seven days of medication. Inan exemplary embodiment, the transdermal patch provides medication forabout three days, before it is desirable to replace the patch. Inanother exemplary embodiment, the transdermal patch provides seven daysof medication, before it is desirable to replace the patch. In addition,the transdermal dosage may be formulated with any desirable dosage of acompound according to the invention. For example, the transdermal dosagemay provide the equivalent dosage to oral administration of 100 mg bid,150 mg bid, 200 mg bid, 250 mg bid, 300 mg bid, 350 mg bid, or 400 mgbid. As such, a transdermal patch(es) having the equivalent dosage tooral administration of 150 mg bid may be administered to a subject for adesired period of time, for example, four weeks, and then a patch orpatches having the equivalent dosage to oral administration of 200 mgbid may be administered for a desired period of time.

Also included within the invention is a kit, which may contain a desiredsupply of patches, for example, a one month supply of transdermalpatches. Optionally, a kit may be organized into a plurality of, e.g.,three, differently identified (numbered, colored or the like) parts,wherein the contents of a first part are initially administered,followed by administration of the contents of a second part, which arethen followed by administration of the contents of the third part.Alternatively, a kit may contain a combination of patches and oralformulations.

V. Subjects and Patient Populations

The term “subject” includes living organisms in which Aβ-amyloidosis canoccur, or which are susceptible to Aβ-amyloid diseases, e.g.,Alzheimer's disease, etc. Examples of subjects include humans, chickens,ducks, Peking ducks, geese, monkeys, deer, cows, rabbits, sheep, goats,dogs, cats, mice, rats, and transgenic species thereof. The term“subject” preferably includes animals susceptible to statescharacterized by neuronal cell death, e.g. mammals, e.g. humans. Theanimal can be an animal model for a disorder, e.g., a transgenic mousewith an Alzheimer's-type neuropathology. In preferred embodiments, thesubject is a mammal, more preferably a human subject.

The term “human subject” includes humans susceptible to benefit fromSAPS administration, and more particularly those susceptible to ordiagnosed of having an amyloid-β related disease and/or suffering from aneurodegenerative disease, such as Alzheimer's disease, Parkinson'sdisease, etc.

In certain embodiments of the invention, the human subject is in need oftreatment by the methods of the invention, and is selected for treatmentbased on this need. A subject in need of treatment is art-recognized,and includes subjects that have been identified as having a disease ordisorder related to β-amyloid deposition, has a symptom of such adisease or disorder, or is at risk of such a disease or disorder, andwould be expected, based on diagnosis, e.g., medical diagnosis, tobenefit from treatment (e.g., curing, healing, preventing, alleviating,relieving, altering, remedying, ameliorating, improving, or affectingthe disease or disorder, the symptom of the disease or disorder, or therisk of the disease or disorder).

For example, the human subject may be a human over 30 years old, humanover 40 years old, a human over 50 years old, a human over 60 years old,a human over 70 years old, a human over 80 years old, a human over 85years old, a human over 90 years old, or a human over 95 years old. Thesubject may be a female human, including a postmenopausal female human,who may be on hormone (estrogen) replacement therapy. The subject mayalso be a male human. In another embodiment, the subject is under 40years old.

In preferred embodiments, the subject is a human subject having anAlzheimer's-type neuropathology. Individuals presently suffering fromAlzheimer's disease can be recognized from characteristic dementia, aswell as the presence of risk factors described below. In addition, anumber of diagnostic tests based on cognitive and neurological testingare available for identifying individuals who have AD. For example,individuals suffering from Alzheimer's disease can be diagnosed by theClinical Dementia Rating (CDR) scale, Mini-mental State Examination(MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale(ADAS-Cog), or any other test known in the art, as discussed herein.Baseline scores on suitable metrics including the MMSE and the ADAStogether with other metrics designed to evaluate a more normalpopulation can be used to find an at risk population. Another method foridentifying an at risk group utilizes an assay for neural thread proteinin the urine; see, e.g., Munzar et al., Neurology and ClinicalNeurophysiology, Vol. 2002, No. 1. Patients with high risk forAlzheimer's Disease can also be selected from a population by screeningfor early signs of memory loss or other difficulties associated withpre-Alzheimer's symptomatology, a family history of Alzheimer's Disease,patients with Mild Cognitive Impairment (MCI), genetic risk factors,age, sex, and other features found to predict high-risk for Alzheimer'sDisease.

The term “prevention” or “preventing” is also used to describe theadministration of a compound or composition of the invention to asubject who is at risk of (or susceptible to) such a disease orcondition. Patients amenable to treatment for prevention of the diseaseor condition include individuals at risk of the disease or condition butnot showing symptoms, as well as patients presently showing symptoms. Inthe case of Alzheimer's disease, virtually anyone is at risk ofsuffering from Alzheimer's disease if he or she lives long enough.Therefore, the present methods can be administered prophylactically tothe general population without any assessment of the risk of the subjectpatient. But the present methods are especially useful for individualswho do have a known risk of Alzheimer's disease. Such individualsinclude those having relatives who have experienced this disease, andthose whose risk is determined by analysis of genetic or biochemicalmarkers, including brain plaques diagnosed by imaging methods, e.g.,MRI, PET, SPECT etc. Examples of such imaging methods are discussed inBurggren et al., Current Topics in Medicinal Chemistry, vol. 2002, no.2, pp. 385-393, and Sair et al., Neuroradiology, vol. 46, pp. 93-104(2002). Alzheimer's disease predisposing factors identified or proposedin the scientific literature include, among others, a genotypepredisposing a subject to Alzheimer's disease; environmental factorspredisposing a subject to Alzheimer's disease; past history of infectionby viral and bacterial agents predisposing a subject to Alzheimer'sdisease; and vascular factors predisposing a subject to Alzheimer'sdisease. Genetic markers of risk toward Alzheimer's disease includemutations in the APP gene, particularly mutations at position 717 andpositions 670 and 671 referred to as the Hardy and Swedish mutationsrespectively (see Hardy et al., TINS 20, 154-158 (1997)). Other markersof risk are mutations in the presenilin genes, PS1 and PS2, and ApoE4,family history of AD, hypercholesterolemia or atherosclerosis. Thesubject may be shown to be at risk by a diagnostic brain imagingtechnique, for example, one that measures brain activity, plaquedeposition, or brain atrophy. The human subject may also be shown to beat risk by a cognitive test such as Clinical Dementia Rating (“CDR”),Alzheimer's disease Assessment Scale-Cognition (“ADAS-Cog”), DisabilityAssessment for Dementia (“DAD”) or Mini-Mental State Examination(“MMSE”) and/or by any other cognition test known in the art.

In another embodiment, the human subject exhibits no symptoms ofAlzheimer's disease. In another embodiment, the subject is at least 40years of age and exhibits no symptoms of Alzheimer's disease. In anotherembodiment, the human subject is at least 40 years of age and exhibitsone or more symptoms of Alzheimer's disease.

By using the methods and compounds of the present invention, the levelsof amyloid β peptides in a subject's plasma or cerebrospinal fluid (CSF)could be significantly reduced from levels prior to treatment from about10 to about 100 percent, or even about 50 to about 100 percent, e.g.,15, 25, 40, 60, 70, 75, 80, 90, 95 or 99%. Accordingly, in certainembodiments, the human subject can have an elevated level of amyloidAβ₄₀ and Aβ₄₂ peptide in the blood and/or CSF prior to a treatmentaccording to the present methods, e.g. Aβ₄₀ levels of greater than about10 pg/mL, or greater than about 20 pg/mL, or greater than about 35pg/mL, or even greater than about 40 pg/mL; and Aβ₄₂ levels 30 pg/mL toabout 200 pg/mL, or even to about 500 pg/mL. Similarly, according tosome embodiments, the methods and compounds of the present inventionhelp reduce the size and/or number of Aβ plaques or Aβ deposits in thebrain, from about 10 to about 100 percent, or even about 50 to about 100percent, e.g., 15, 25, 40, 60, 70, 75, 80, 90, 95 or 99%, when comparedto levels prior to treatment.

VI. Pharmaceutical Compositions

Preferably, the compounds of the invention are formulated prior toadministration into pharmaceutical compositions using techniques andprocedures well known in the art. Accordingly, in another embodiment,the present invention relates to pharmaceutical compositions (e.g.solutions, suspensions or emulsions) comprising effective amounts of oneor more compounds according to any of the Formulae herein and apharmaceutically acceptable vehicle, as well as methods of using andmanufacturing such pharmaceutical compositions.

The pharmaceutical compositions are formulated into suitableadministration (orally, parenterally, (IV, IM, depo-IM, SC, and depoSC), sublingually, intranasally (inhalation), intrathecally, topically,or rectally). Suitable pharmaceutically acceptable vehicles include,without limitation, any non-immunogenic pharmaceutical carrier ordiluent suitable for oral, parenteral, nasal, mucosal, transdermal,topical, intrathecal, rectal, intravascular (IV), intraarterial (IA),intramuscular (IM), and subcutaneous (SC) administration routes, such asphosphate buffer saline (PBS). Also, the present invention includes suchcompounds which have been lyophilized and which may be reconstituted toform pharmaceutically acceptable formulations for administration, as byintravenous, intramuscular, or subcutaneous injection. Administrationmay also be intradermal or transdermal.

The vehicle can be a solvent or dispersion medium containing, forexample, water, ethanol, polyol (for example, glycerol, propyleneglycol, and liquid polyethylene glycol, and the like), suitable mixturesthereof, and vegetable oils. The proper fluidity can be maintained, forexample, by the use of a coating such as lecithin, by the maintenance ofthe required particle size in the case of dispersion and by the use ofsurfactants. Prevention of the action of microorganisms can be achievedby various antibacterial and antifungal agents, for example, parabens,chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In manycases, isotonic agents are included, for example, sugars, sodiumchloride, or polyalcohols such as mannitol and sorbitol, in thecomposition. Prolonged absorption of the injectable compositions can bebrought about by including in the composition an agent which delaysabsorption, for example, aluminum monostearate or gelatin.

Preferably, the compound(s) of the invention can be orally administered.Formulations of the present invention include those suitable for oraladministration. The formulations may conveniently be presented in unitdosage form and may be prepared by any methods well known in the art ofpharmacy. Methods of preparing these formulations or compositionsinclude the step of bringing into association a compound of the presentinvention with a pharmaceutically acceptable vehicle (e.g. an inertdiluent or an assimilable edible carrier) and, optionally, one or moreaccessory ingredients. In general, the formulations are prepared byuniformly and intimately bringing into association a compound of thepresent invention with liquid carriers, or finely divided solidcarriers, or both, and then, if necessary, shaping the product. Theamount of the therapeutic agent in such therapeutically usefulcompositions is such that a suitable dosage will be obtained.

Formulations of the invention suitable for oral administration may be inthe form of capsules (e.g. hard or soft shell gelatin capsule), cachets,pills, tablets, lozenges, powders, granules, pellets, dragees, e.g.,coated (e.g., enteric coated) or uncoated, or as a solution or asuspension in an aqueous or non-aqueous liquid, or as an oil-in-water orwater-in-oil liquid emulsion, or as an elixir or syrup, or as pastilles(using an inert base, such as gelatin and glycerin, or sucrose andacacia) or as mouth washes and the like, each containing a predeterminedamount of a compound of the present invention as an active ingredient. Acompound of the present invention may also be administered as a bolus,electuary or paste, or incorporated directly into the subject's diet.Moreover, in certain embodiments these pellets can be formulated to (a)provide for instant or rapid drug release (i.e., have no coating onthem); (b) be coated, e.g., to provide for sustained drug release overtime; or (c) be coated with an enteric coating for bettergastrointestinal tolerability.

In solid dosage forms of the invention for oral administration theactive ingredient is mixed with one or more pharmaceutically acceptablecarriers, such as sodium citrate or dicalcium phosphate, or any of thefollowing: fillers or extenders, such as starches, lactose, sucrose,glucose, mannitol, or silicic acid; binders, such as, for example,carboxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone,sucrose or acacia; humectants, such as glycerol; disintegrating agents,such as agar-agar, calcium carbonate, potato or tapioca starch, alginicacid, certain silicates, and sodium carbonate; solution retardingagents, such as paraffin; absorption accelerators, such as quaternaryammonium compounds; wetting agents, such as, for example, cetyl alcoholand glycerol monostearate; absorbents, such as kaolin and bentoniteclay; lubricants, such as talc, calcium stearate, magnesium stearate,solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof;and coloring agents. In the case of capsules, tablets and pills, thepharmaceutical compositions may also comprise buffering agents. Solidcompositions of a similar type may also be employed as fillers in softand hard-filled gelatin capsules using such excipients as lactose ormilk sugars, as well as high molecular weight polyethylene glycols andthe like.

Peroral compositions typically include liquid solutions, emulsions,suspensions, and the like. The pharmaceutically acceptable vehiclessuitable for preparation of such compositions are well known in the art.Typical components of carriers for syrups, elixirs, emulsions andsuspensions include ethanol, glycerol, propylene glycol, polyethyleneglycol, liquid sucrose, sorbitol and water. For a suspension, typicalsuspending agents include methyl cellulose, sodium carboxymethylcellulose, tragacanth, and sodium alginate; typical wetting agentsinclude lecithin and polysorbate 80; and typical preservatives includemethyl paraben and sodium benzoate. Peroral liquid compositions may alsocontain one or more components such as sweeteners, flavoring agents andcolorants disclosed above.

Pharmaceutical compositions suitable for injectable use include sterileaqueous solutions (where water soluble) or dispersions, and sterilepowders for the extemporaneous preparation of sterile injectablesolutions or dispersion. In all cases, the composition must be sterileand must be fluid to the extent that easy syringability exists. It mustbe stable under the conditions of manufacture and storage and must bepreserved against the contaminating action of microorganisms such asbacteria and fungi. Sterile injectable solutions can be prepared byincorporating the therapeutic agent in the required amount in anappropriate solvent with one or a combination of ingredients enumeratedabove, as required, followed by filtered sterilization. Generally,dispersions are prepared by incorporating the therapeutic agent into asterile vehicle which contains a basic dispersion medium and therequired other ingredients from those enumerated above. In the case ofsterile powders for the preparation of sterile injectable solutions, themethods of preparation are vacuum drying and freeze-drying which yieldsa powder of the active ingredient (i.e., the therapeutic agent) plus anyadditional desired ingredient from a previously sterile-filteredsolution thereof.

Pharmaceutical formulations are also provided which are suitable foradministration as an aerosol, by inhalation. These formulations comprisea solution or suspension of the desired compound of any Formula hereinor a plurality of solid particles of such compound(s). The desiredformulation may be placed in a small chamber and nebulized. Nebulizationmay be accomplished by compressed air or by ultrasonic energy to form aplurality of liquid droplets or solid particles comprising the agents orsalts. The liquid droplets or solid particles should have a particlesize in the range of about 0.5 to about 5 microns. The solid particlescan be obtained by processing the solid agent of any Formula describedherein, or a salt thereof, in any appropriate manner known in the art,such as by micronization. The size of the solid particles or dropletswill be, for example, from about 1 to about 2 microns. In this respect,commercial nebulizers are available to achieve this purpose.

A pharmaceutical formulation suitable for administration as an aerosolmay be in the form of a liquid, the formulation will comprise awater-soluble agent of any Formula described herein, or a salt thereof,in a carrier which comprises water. A surfactant may be present whichlowers the surface tension of the formulation sufficiently to result inthe formation of droplets within the desired size range when subjectedto nebulization.

The compositions of this invention can also be administered topically toa subject, e.g., by the direct laying on or spreading of the compositionon the epidermal or epithelial tissue of the subject, or transdermallyvia a “patch”. Such compositions include, for example, lotions, creams,solutions, gels and solids. These topical compositions may comprise aneffective amount, usually at least about 0.1%, or even from about 1% toabout 5%, of an agent of the invention. Suitable carriers for topicaladministration typically remain in place on the skin as a continuousfilm, and resist being removed by perspiration or immersion in water.Generally, the carrier is organic in nature and capable of havingdispersed or dissolved therein the therapeutic agent. The carrier mayinclude pharmaceutically acceptable emollients, emulsifiers, thickeningagents, solvents and the like.

Other compositions useful for attaining systemic delivery of the subjectagents include sublingual, buccal and nasal dosage forms. Suchcompositions typically comprise one or more of soluble filler substancessuch as sucrose, sorbitol and mannitol; and binders such as acacia,microcrystalline cellulose, carboxymethyl cellulose and hydroxypropylmethyl cellulose. Glidants, lubricants, sweeteners, colorants,antioxidants and flavoring agents disclosed above may also be included.The compound(s) of the invention may also be administered parenterally,intraperitoneally, intraspinally, or intracerebrally. For suchcompositions, the compound(s) of the invention can be prepared inglycerol, liquid polyethylene glycols, and mixtures thereof and in oils.Under ordinary conditions of storage and use, these preparations maycontain a preservative to prevent the growth of microorganisms.

To administer the compound(s) of the invention by other than parenteraladministration, it may be useful to coat the compound(s) with, orco-administer the compound(s) with a material to prevent itsinactivation. For example, the compound(s) of the invention may beadministered to a subject in an appropriate carrier, for example,liposomes, or a diluent. Pharmaceutically acceptable diluents includesaline and aqueous buffer solutions. Liposomes includewater-in-oil-in-water CGF emulsions as well as conventional liposomes.

Pharmaceutical compositions according to the invention may also becoated by conventional methods, typically with pH or time-dependentcoatings, such that the compound(s) of the invention is released in thevicinity of the desired location, or at various times to extend thedesired action. Such dosage forms typically include, but are not limitedto, one or more of cellulose acetate phthalate, polyvinylacetatephthalate, hydroxypropyl methyl cellulose phthalate, ethyl cellulose,waxes, and shellac.

The compound(s) of the invention may be packaged as part of a kit,optionally including a container (e.g. packaging, a box, a vial, etc).The kit may be commercially used according to the methods describedherein and may include instructions for use in a method of theinvention. Additional kit components may include acids, bases, bufferingagents, inorganic salts, solvents, antioxidants, preservatives, or metalchelators. The additional kit components are present as purecompositions, or as aqueous or organic solutions that incorporate one ormore additional kit components. Any or all of the kit componentsoptionally further comprise buffers.

VII. Dosage

Dosage forms, upon releasing a compound according to the invention, canprovide the corresponding 3APS upon in vivo administration to a humanpatient. It is understood that appropriate doses depend upon a number offactors within the knowledge of the ordinarily skilled physician,veterinarian, or researcher (e.g. see Wells et al. eds., PharmacotherapyHandbook, 2^(nd) Edition, Appleton and Lange, Stamford, Conn. (2000);PDR Pharmacopoeia, Tarascon Pocket Pharmacopoeia 2000, Deluxe Edition,Tarascon Publishing, Loma Linda, Calif. (2000)). The dose(s) of thecompound(s) of the invention will vary, for example, depending upon avariety of factors including the activity of the specific agentemployed, the age, body weight, general health, gender, and diet of thesubject, the time of administration, the route of administration, therate of excretion, and any drug combination, if applicable, the effectwhich the practitioner desires the compound to have upon the subject andthe properties of the compounds (e.g. bioavailability, stability,potency, toxicity, etc). Such appropriate doses may be determined usingthe assays described herein. When one or more of the compounds of theinvention is to be administered to humans, a physician may for example,prescribe a relatively low dose at first, subsequently increasing thedose until an appropriate response is obtained.

Exemplary doses include milligram or microgram amounts of the compoundper kilogram of subject or sample weight (e.g., about 50 micrograms perkilogram to about 500 milligrams per kilogram, about 1 milligram perkilogram to about 100 milligrams per kilogram, about 1 milligram perkilogram to about 50 milligram per kilogram, about 1 milligram perkilogram to about 10 milligrams per kilogram, or about 3 milligrams perkilogram to about 5 milligrams per kilogram). Additional exemplary dosesinclude doses of about 5 to about 500 mg, or about 25 to about 300 mg,or about 25 to about 200 mg, preferably about 50 to about 150 mg, morepreferably about 50, about 100, about 150 mg, about 200 mg or about 250mg, and, preferably, daily or twice daily, or lower or higher amounts.For comparison, exemplary doses for 3APS per se include about 2-3milligram of 3APS per kilogram of subject (twice daily). See also U.S.Ser. No. 11/103,656, filed on Apr. 12, 2005, which is incorporatedherein by reference.

It is generally advantageous to formulate parenteral compositions indosage unit form for ease of administration and uniformity of dosage.The term “unit dosage form” refers to a physically discrete unitsuitable as unitary dosages for human subjects and other mammals, eachunit containing a predetermined quantity of active material calculatedto produce the desired therapeutic effect, in association with asuitable pharmaceutical vehicle. In an embodiment, the compositionsaccording to the invention are formulated in a unit dosage form, eachdosage containing from about 50 mg to about 500 mg, more preferablyabout 100 mg to about 300 mg of the compound according to the invention.See also U.S. Ser. No. 11/103,656, filed on Apr. 12, 2005, which isincorporated herein by reference. The specification for the dosage unitforms of the invention may vary and are dictated by and directlydependent on (a) the unique characteristics of the therapeutic agent andthe particular therapeutic effect to be achieved, and (b) thelimitations inherent in the art of compounding such a therapeutic agentfor the treatment of amyloid deposition in subjects.

Administration of the compounds and compositions of the presentinvention to a subject to be treated can be carried out using knownprocedures, at dosages and for periods of time effective to achieved adesired purposes (e.g. prevention or treatment of AD, obtaining specificlevels of 3APS, etc). Dosage regimens can be adjusted to provide theoptimum therapeutic response. For example, several divided doses may beadministered daily or the dose may be proportionally reduced asindicated by the exigencies of the therapeutic situation.

In one embodiment, the compound(s) of the invention is administered at atherapeutically effective dosage sufficient to inhibit amyloiddeposition in a subject, preferably a human subject. When referring toamyloid deposition a “therapeutically effective” dosage inhibits amyloiddeposition by, for example, at least about 20%, or by at least about40%, or even by at least about 60%, or by at least about 80% relative tountreated subjects.

In one embodiment, the compound(s) of the invention is administered at atherapeutically effective dosage for the prevention or treatment ofAlzheimer's. When referring to Alzheimer's, a “therapeuticallyeffective” dosage stabilizes cognitive function or prevents a furtherdecrease in cognitive function (i.e., preventing, slowing, or stoppingdisease progression).

VII. Uses of Compounds, Composition, and Dosage Forms

Another aspect of the invention pertains to a method for inhibitingneuronal cell death by administering an effective amount of a compoundof the present invention. In yet another aspect, the invention pertainsto a method for providing neuroprotection to a subject having anAβ-amyloid related disease, e.g. Alzheimer's disease, which includesadministering an effective amount of a compound of the present inventionto the subject, such that neuroprotection is provided. As used herein,the term “neuroprotection” includes protection of neuronal cells of asubject from cell death that may result in initiation of processes suchas, but not limited to: the destabilization of the cytoskeleton; DNAfragmentation; the activation of hydrolytic enzymes, such asphospholipase A2; activation of caspases, calcium-activated proteasesand/or calcium-activated endonucleases; inflammation mediated bymacrophages; calcium influx into a cell; membrane potential changes in acell; the disruption of cell junctions leading to decreased or absentcell-cell communication; and the activation of expression of genesinvolved in cell death.

According to a preferred embodiment, the compounds and compositions ofthe present invention are used for one or more of the following: toprevent Alzheimer's disease, to treat Alzheimer's disease, or amelioratesymptoms of Alzheimer's disease, to regulate production of or levels ofamyloid β (Aβ) peptides, prevent, reduce, or inhibit amyloid depositionin a subject, and to treat or prevent of amyloid-related diseases.

The compounds and pharmaceutical compositions of the invention may actto ameliorate the course of a β-amyloid related disease using any of thefollowing mechanisms (this list is meant to be illustrative and notlimiting): slowing the rate of β-amyloid fibril formation or deposition;lessening the degree of β-amyloid deposition; inhibiting, reducing, orpreventing amyloid fibril formation; inhibiting neurodegeneration orcellular toxicity induced by β-amyloid; inhibiting amyloid inducedinflammation; enhancing the clearance of β-amyloid from the brain;enhancing degradation of Aβ in the brain; or favoring clearance ofamyloid protein prior to its organization in fibrils, and decreasing theratio of Aβ42:Aβ40 in the CSF or plasma. In another embodiment, theinvention pertains to a method for improving cognition in a subjectsuffering from AD. The method includes administering an effective amountof a therapeutic compound of the invention, such that the subject'scognition is improved. The subject's cognition can be tested usingmethods known in the art such as the Clinical Dementia Rating (“CDR”),Mini-Mental State Examination (“MMSE”), Disability Assessment forDementia (“DAD”), and the Alzheimer's Disease Assessment Scale-Cognition(“ADAS-Cog”). Improvement in cognition is present within the context ofthe present invention if there is a measurable difference between theperformances of subjects treated using the methods of the invention ascompared to members of a placebo group, historical control, or betweensubsequent tests given to the same subject. The invention also pertainsto a method for treating, slowing or stopping a β-amyloid relateddisease associated with cognitive impairment, by administering to asubject an effective amount of a therapeutic compound of the invention,wherein the annual deterioration of the subject's cognition as measuredby any of the foregoing mentioned test is improved.

It is to be understood that wherever values and ranges are providedherein, e.g., in ages of subject populations, dosages, and blood levels,all values and ranges encompassed by these values and ranges, are meantto be encompassed within the scope of the present invention. Moreover,all values in these values and ranges may also be the upper or lowerlimits of a range.

VIII. Combination Therapy

In certain embodiments, the compounds and composition according to theinvention can be used in combination therapy with at least one othertherapeutic agent. The prodrug compounds according to the invention andthe at least one other therapeutic agent(s) can act additively or, incertain embodiments, synergistically. In certain embodiments, thecompounds of the invention can be administered concurrently with theadministration of another therapeutic agent. In certain embodiments, thecompounds of the invention can be administered prior or subsequent toadministration of another therapeutic agent. The at least one othertherapeutic agent can be effective for treating the same or differentdisease, disorder, or condition.

Methods of the present invention include administration of one or morecompounds or pharmaceutical compositions of the present invention andone or more other therapeutic agents provided that the combinedadministration does not inhibit the therapeutic efficacy of the one ormore compounds of the present invention and/or does not produce adversecombination effects.

In certain embodiments, compositions of the present invention can beadministered concurrently with the administration of another therapeuticagent, which can be part of the same pharmaceutical composition as, orin a different composition from, that containing the compounds of thepresent invention. In certain embodiments, compounds of the presentinvention can be administered prior or subsequent to administration ofanother therapeutic agent. In certain embodiments of combinationtherapy, the combination therapy comprises alternating betweenadministering a composition of the present invention and a compositioncomprising another therapeutic agent, e.g., to minimize adverse sideeffects associated with a particular drug. When a compound of thepresent invention is administered concurrently with another therapeuticagent that potentially can produce adverse side effects including, butnot limited to, toxicity, the therapeutic agent can advantageously beadministered at a dose that falls below the threshold at which theadverse side effect is elicited.

In certain embodiments, a pharmaceutical composition can furthercomprise substances to enhance, modulate and/or control release,bioavailability, therapeutic efficacy, therapeutic potency, stability,and the like. For example, to enhance therapeutic efficacy a compound ofthe present invention, the compound can be co-administered with one ormore active agents to increase the absorption or diffusion of thecompound from the gastrointestinal tract, or to inhibit degradation ofthe drug in the systemic circulation. In certain embodiments, at leastone compound of the present invention can be co-administered with activeagents having a pharmacological effect that enhance the therapeuticefficacy of SAPS.

In certain embodiments, compounds or pharmaceutical compositions of thepresent invention include, or can be administered to a patient togetherwith, another therapeutic drug that may be available over-the-counter orby prescription. US patent application No. 2005/0031651 (incorporatedherein by reference) provide a long but non-exhaustive list of“therapeutic drugs” that can be useful, in combination, according to theinvention. Preferred therapeutic drugs to be used with the compounds orpharmaceutical compositions of the present invention are therapeuticdrugs useful in the prevention or treatment of Alzheimer's Disease orits symptoms, including but not limited to donepezil (Aricept™),memantine (Namenda™), rivastigmine (Exelon™), Galanthamine (Reminyl™ andR-flurbiprofen (Flurizan™). The compounds and compositions according tothe invention could also be combined with vaccines and antibodies forthe prevention or treatment of AD.

In a further embodiment, the compounds of the invention can beco-administered with 3APS.

IX. Standard Methods for Testing the Compounds of the Invention

The compounds according to the invention can be further analyzed, testedor validated using a variety of in vitro assays, or in vivo assays toconfirm their safety, bioavailabity, neuroprotection, their capabilityto deliver 3APS etc. The following are illustrative of the type ofbiological assays that can be conducted to assess the instant compounds.

i) Determination of Enzymatic Cleavage of Prodrugs In Vitro

For orally administered prodrugs, it is generally desirable that theprodrug remains intact (i.e., uncleaved) while in the gastrointestinaltract and be cleaved (i.e., to release the parent drug) while in thesystemic circulation. A useful level of stability can at least in partbe determined by the mechanism and kinetics of absorption of the prodrugby the gastrointestinal tract. A useful level of lability can at leastin part be determined by the pharmacokinetics of the prodrug and parentdrug in the systemic circulation. In general, prodrugs that are morestable in a Caco-2 S9 and/or pancreatin assay and are more labile in arat plasma, human plasma, rat liver S9, and/or human liver S9preparation can be useful as an orally administered prodrug. The resultsof tests, for determining the enzymatic cleavage of prodrugs in vitrocan be used to select prodrugs for in vivo testing.

ii) Bioavailability of Prodrugs In Vivo

Prodrugs that provide a bioavailability of the corresponding parent drugthat is greater than the bioavailability provided by an equimolar doseof the parent drug administered to a patient by the same route (e.g.,oral administration) can be useful as therapeutic agents.Bioavailability of the compounds of the invention and of released 3APScan be measured in vivo (humans and laboratory animals) using methodswell known in the art. Example 3 herein provides an exemplary method forassessing bioavailability in mice.

iii) In Vivo Assays: Animal Models

Various animal models can be used to the efficacy and/or potency of thecompound according to the invention. For example, certain transgenicanimal models have been described, for example, in U.S. Pat. Nos.5,877,399; 5,612,486; 5,387,742; 5,720,936; 5,850,003; 5,877,015, and5,811,633, and in Ganes et al., (Nature 1995, 373:523). Preferred areanimal models that exhibit characteristics associated with thepathophysiology of AD. Administration of the compound inhibitors of theinvention to the transgenic mice described herein provides analternative method for demonstrating the inhibitory activity of thecompounds. Administration of the compounds in a pharmaceuticallyeffective carrier and via an administrative route that reaches thetarget tissue in an appropriate therapeutic amount is also preferred.

iv) Toxicity

A variety of different parameters can be monitored to assess toxicity.Examples of such parameters include, but are not limited to, cellproliferation, monitoring activation of cellular pathways fortoxicological responses by gene or protein expression analysis, DNAfragmentation, changes in the composition of cellular membranes,membrane permeability, activation of components of death-receptors ordownstream signaling pathways (e.g., caspases), generic stressresponses, NF-kappaB activation and responses to mitogens. Relatedassays are used to assay for apoptosis (a programmed process of celldeath) and necrosis, including cGMP formation and NO formation.

Toxicity and therapeutic efficacy of the compound(s) and composition(s)of the invention can be determined by standard pharmaceutical proceduresin cell cultures or experimental animals, e.g., for determining the LD50(the dose lethal to 50% of the population) and the ED50 (the dosetherapeutically effective in 50% of the population). The dose ratiobetween toxic and therapeutic effects is the therapeutic index and canbe expressed as the ratio LD50/ED50, and usually a larger therapeuticindex is more efficacious. While agents that exhibit toxic side effectsmay be used, care should be taken to design a delivery system thattargets such agents to the site of affected tissue in order to minimizepotential damage to unaffected cells and, thereby, reduce side effects.

v) Neuroprotection

The following are illustrative of the type of biological assays that canbe conducted to assess whether a inhibitory agent has a protectiveeffect against neuronal injury or disease.

a. Morphological Changes

Apoptosis in many cell types is correlated with altered morphologicalappearances. Examples of such alterations include, but are not limitedto, plasma membrane blebbing, cell shape change, loss of substrateadhesion properties. Such changes are readily detectable with a lightmicroscope. Cells undergoing apoptosis can also be detected byfragmentation and disintegration of chromosomes. These changes can bedetected using light microscopy and/or DNA or chromatin specific dyes.

b. Altered Membrane Permeability

Often the membranes of cells undergoing apoptosis become increasinglypermeable. This change in membrane properties can be readily detectedusing vital dyes (e.g., propidium iodide and trypan blue). Dyes can beused to detect the presence of necrotic cells. For example, certainmethods utilize a green-fluorescent LIVE/DEAD™ Cytotoxicity Kit #2,available from Molecular Probes. The dye specifically reacts withcellular amine groups. In necrotic cells, the entire free amine contentis available to react with the dye, thus resulting in intensefluorescent staining. In contrast, only the cell-surface amines ofviable cells are available to react with the dye. Hence, thefluorescence intensity for viable cells is reduced significantlyrelative to necrotic cells (see, e. g., Haugland, 1996 Handbook ofFluorescent Probes and Research Chemicals, 6th ed., Molecular Probes,OR).

c. Dysfunction of Mitochondrial Membrane Potential

Mitochondria provide direct and indirect biochemical regulation ofdiverse cellular processes as the main energy source in cells of higherorganisms. These process include the electron transport chain activity,which drives oxidative phosphorylation to produce metabolic energy inthe form of adenosine triphosphate (i.e., ATP). Altered or defectivemitochondrial activity can result in mitochondrial collapse called the“permeability transition” or mitochondrial permeability transition.Proper mitochondrial functioning requires maintenance of the membranepotential established across the membrane. Dissipation of the membranepotential prevents ATP synthesis and thus halts or restricts theproduction of a vital biochemical energy source.

Consequently, a variety of assays designed to assess toxicity and celldeath involve monitoring the effect of a test agent on mitochondrialmembrane potentials or on the mitochondrial permeability transition. Oneapproach is to utilize fluorescent indicators (see, e.g., Haugland, 1996Handbook of Fluorescent Probes and Research Chemicals, 6th ed.,Molecular Probes, OR, pp. 266-274 and 589-594). Various non-fluorescentprobes can also be utilized (see, e.g., Kamo et al. (1979) J. MembraneBiol. 49:105). Mitochondrial membrane potentials can also be determinedindirectly from mitochondrial membrane permeability (see, e.g., Quinn(1976) The Molecular Biology of Cell Membranes, University Park Press,Baltimore, Md., pp. 200-217). Further guidance on methods for conductingsuch assays is provided in PCT publication WO 00/19200 to Dykens et al.

d. Caspase Activation

Apoptosis is the process of programmed cell death and involves theactivation of a genetic program when cells are no longer needed or havebecome seriously damaged. Apoptosis involves a cascade of biochemicalevents and is under the regulation of a number of different genes. Onegroup of genes act as effectors of apoptosis and are referred to as theinterleukin-1β converting enzyme (ICE) family of genes. These genesencode a family of cysteine proteases whose activity is increased inapoptosis. The ICE family of proteases is generically referred to ascaspase enzymes. The “C” in the name reflects the fact that the enzymesare cysteine proteases, while “Caspase” refers to the ability of theseenzymes to cleave after aspartic acid residues.

Consequently, some assays for apoptosis are based upon the observationthat caspases are induced during apoptosis. Induction of these enzymescan be detected by monitoring the cleavage of specifically-recognizedsubstrates for these enzymes. A number of naturally occurring andsynthetic protein substrates are known (see, e.g., Ellerby et al. (1997)J. Neurosci. 17:6165; Kluck, et al. (1997) Science 275:1132; Nicholsonet al. (1995) Nature 376:37; and Rosen and Casciola-Rosen (1997) J. CellBiochem. 64:50). Methods for preparing a number of different substratesthat can be utilized in these assays are described in U.S. Pat. No.5,976,822. This patent also describes assays that can be conducted usingwhole cells that are amendable to certain of the microfluidic devicesdescribed herein. Other methods using FRET techniques are discussed inMahajan, et al. (1999) Chem. Biol. 6:401-9; and Xu, et al. (1998) Nucl.Acids. Res. 26:2034-5.

e. Cytochrome C Release

In healthy cells, the inner mitochondrial membrane is impermeable tomacromolecules. Thus, one indicator of cell apoptosis is the release orleakage of cytochrome C from the mitochondria. Detection of cytochrome Ccan be performed using spectroscopic methods because of the inherentabsorption properties of the protein. Thus, one detection option withthe present devices is to place the cells within a holding space andmonitor absorbance at a characteristic absorption wavelength forcytochrome C. Alternatively, the protein can be detected using standardimmunological methods (e.g., ELISA assays) with an antibody thatspecifically binds to cytochrome C (see, e.g., Liu et al. (1996) Cell86:147).

f. Assays for Cell Lysis

The final stage of cell death is typically lysis of the cell. When cellsdie they typically release a mixture of chemicals, includingnucleotides, and a variety of other substances (e.g., proteins andcarbohydrates) into their surroundings. Some of the substances releasedinclude ADP and ATP, as well as the enzyme adenylate cyclase, whichcatalyzes the conversion of ADP to ATP in the presence of excess ADP.Thus, certain assays involve providing sufficient ADP in the assaymedium to drive the equilibrium towards the generation of ATP which cansubsequently be detected via a number of different means. One suchapproach is to utilize a luciferin/luciferase system that is well knownto those of ordinary skill in the art in which the enzyme luciferaseutilizes ATP and the substrate luciferin to generate a photometricallydetectable signal. Further details regarding certain cell lysis assaysthat can be performed are set forth in PCT publication WO 00/70082.

g. Ischemic Model Systems

Methods for assaying whether a compound can confer protectiveneurological effects against ischemia and stroke are discussed by Aarts,et al. (Science 298:846-850, 2002). In general, this assay involvessubjecting rats to a middle cerebral artery occlusion (MCAO) for arelatively short period of time (e.g., about 90 minutes). MCAO can beinduced using various methods, including an intraluminal suture method(see, e.g., Longa, E. Z. et al. (1989) Stroke 20:84; and Belayev, L., etal. (1996) Stroke 27:1616). A composition containing the putativeinhibitor is introduced into the rat using conventional methods (e.g.,via intravenous injection). To evaluate the compositions prophylacticeffect, the composition is administered before performing MCAO. If thecompound is to be evaluated for its ability to mitigate against anischemic event that has already occurred, the composition with thecompound is introduced after MCAO has been initiated. The extent ofcerebral infarction is then evaluated using various measures ofneurological function. Examples of such measures include the posturalreflex test (Bederson, J. B. et al. (1986) Stroke 17:472) and theforelimb placing test (De Ryck, M. et al. (1989) Stroke 20:1383).Methods are also described in Aarts et al assessing the effects ofNMDA-induced excitotoxicity using in vitro assays.

h. MTT Cytotoxicity Assay

The MTT assay is another assay which has been widely used to assesscytotoxicity in neuronal cells. The cellular toxicity can assessed usingthe 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)assay (Trevigen, Gaithersburg, Md.) following the recommendations of themanufacturer.

i. Trypan Blue Cell Viability Measurement

Cell viability can be measured using the trypan blue exclusion method(Yao et al., Brain Res., 889, 181-190 (2001)).

j. Determination of Cellular ATP Levels

Cellular ATP Levels can be indicative of cell viability. Cellular ATPconcentrations can be measured using the ATPLite-M® luminescence assay(Packard BioSciences Co.). For example, in this assay, cells typicallyare cultured on black 96-well ViewPlate® and the ATP concentrations aremeasured on a TopCount NXT® counter (Packard BioSciences Co.) followingthe recommendations of the manufacturer.

vi) Gastrointestinal Absorption

The compounds or drugs according to the invention can be furtheranalyzed, tested or validated for their ability to be absorbed by thegut and/or intestine if so desired.

Intestinal permeability and transport of a drug candidate may beestimated using a variety of in vitro, in situ, as well as in vivomodels (Balimane et al. (2000) J Pharmacol Toxicol Methods 44:385-401;Hidalgo I. (2001) Curr Top Med Chem 1:385-401, Hillgreen K, Kato A andBorchardt R. (1995) 15:83-109).

For instance, parallel artificial membrane permeability (PAMPA) assayand cell-based systems such as Caco-2 and Mardin-Darby canine kidney(MDCK) cells are the most frequently used in vitro models. The PAMPAmodel consists of a hydrophobic filter material coated with a mixture oflecithin/phospholipids dissolved in an inert organic solvent creating anartificial lipid membrane barrier that mimics the intestinal epithelium.Caco-2 cells, a human colon adenocarcinoma, undergo spontaneousenterocytic differentiation in culture and become polarized cells withwell-established tight junctions, resembling intestinal epithelium inhumans. Caco-2 cell model has been the most popular and the mostextensively characterized cell-based model in examining the permeabilityof drugs in, both the pharmaceutical industries and academia.Alternatively, MDCK cells which also develop tight junctions and formmonolayers of polarized cells are used.

An in situ study such as an intestinal perfusion could also be performedto assess drug absorption. Isolated intestinal segments comprise theabsorptive cells and the underlying muscle layers. As it is commonlyused, this technique only allows sampling from the mucosal side; drugdisappearance is assumed to be equal to drug absorption. Typically, awhole animal absorption study (pharmacokinetic study) will be performedin parallel with the in vitro and/or in situ studies to assessintestinal permeability. In general, drug absorption in animals isbelieved to be a good predictor of absorption in humans.

vii) Gastrointestinal Toxicity

The compounds or drugs according to the invention can be furtheranalyzed, tested or validated for gastrointestinal (GI) toxicity.Gastrointestinal toxicity of a compound in vivo can be reliablyestablished through the implementation of a standard battery of generaltoxicological assessments. Generally, regulatory test guidelines fromthe EU, OECD, ICH, FDA and JMOHW are used as reference material for thepreparation of study protocols for such assessments. In North America,the toxicological assessments will generally be carried out incompliance with the United States Food and Drug Administration Title 21Code of Federal Regulations Part 58, Good Laboratory Practice forNon-clinical studies issued on Dec. 22, 1978, Federal Register plussubsequent amendments.

Within the context of such a non-clinical assessment of the toxicity ofa particular compound, GI toxicity may specifically be assessed throughthe monitoring of body weight gain, the gross examination of materialsemitted by the test subject (specifically vomitus and feces) and themonitoring of food/water consumption (appetence). Furthermore, upontermination of a non-clinical toxicological assessment, the retentionand processing of GI tract tissues from the test subject(s) to the slidestage, followed by histopathological examination of said tissues by atrained pathologist, is a useful tool, complementary to theaforementioned “in-life” observations.

viii) Crossing of the Blood Brain Barrier (BBB)

The blood-brain barrier (BBB) is a very specialized barrier system ofendothelial cells that separates the blood from the underlying braincells, providing protection to brain cells and preserving brainhomeostasis. The brain endothelium has a complex arrangement of tightjunctions between the cells that restrict the passage of molecules.Typically the BBB is permeable to small and lipophilic molecules, butlarger molecules are generally not transported across unless there is anactive transport system available. Thus this is one of the stumblingblocks for drug delivery. An additional problem is the very effectivedrug efflux systems (P-glycoprotein), which pump the drug back out ofcells.

The compounds according to the invention can be further analyzed, testedor validated for their ability to cross the BBB is so desired. Manyin-vitro, in-vivo and in-silico methods may be employed during drugdevelopment to mimic the BBB (Lohmann et al. (2002) Predictingblood-brain barrier permeability of drugs: evaluation of different invitro assays. J Drug Target 10:263-276; Nicolazzo et al. (2006) Methodsto assess drug permeability across the blood-brain barrier. J PharmPharmacol 58:281-293). In-vitro models include primary endothelial cellculture and immortalized cell lines such as Caco-2, BMEC, MDCK. Thesecells are useful as a screening method and can appropriately rankcompounds in order of BBB permeability. In vivo models such as theinternal carotid artery single injection or perfusion, intravenous bolusinjection, brain efflux index and intracerebral microdialysis providemore accurate information regarding brain uptake, and these can becomplemented with novel imaging techniques (such as magnetic resonanceimaging and positron emission tomography), although such methods are notsuited to high-throughput permeability assessment.

ix) Brain and CSF Level

The brain and/or cerebrospinal fluid (CSF) levels of the compounds ordrugs according to the invention can be assessed, measured or estimatedusing various models methods, and assays (see Potchoiba M J, andNocerini, M R (2004) DMD 32:1190-1198; Orlowska-Madjack M. (2004) ActaNeurobiol Exp 64: 177-188; and Hocht, C, Opezza, J A and Taira, C A(2004) Curr Drug Discov Technol 1:269-85)

One of the most common techniques is probably a brain sampling after awhole animal absorption study (pharmacokinetic). For instance,pharmacokinetics (PK) profiles of the compound of the invention could beinvestigated using typical nonclinical PK studies in mice. Briefly, atdifferent time-points following intravenous, subcutaneous and oralcompound administrations, brain, CSF and plasma samples are collected.The brain, CSF and plasma samples are then analyzed by LC/MS todetermine the concentration-time profiles of the compound.

Alternatives such as brain dialysis or distribution of a radiolabelledcompound with or without autoradioluminography could also be used. Atypical example is a tissue distribution study to assess the time courseelimination of radioactivity from tissues following the administrationof a known quantity of radiolabeled compound, the percentage of theoriginal dose transported in the brain or CSF can be determined.Furthermore, autoradioluminography of cryosections containing braintissues with a wide range of radioactivity concentrations can be readilyquantified to determine brain levels of a drug.

Alternatively, microdialysis offers a way to remove drugs from thebrain. The principle of microdialysis is based on the diffusion ofmolecules through small-diameter pores of a semi permeable membranetubing connected to a probe that is implanted into a defined brain area.The probe is connected to a perfusion pump and perfused with a liquid,which equilibrates with the fluid outside the tube by diffusion in bothdirections. A quantitative analysis of drug in the fraction-collectedmicrodialysates reflects their concentration in the fluid.

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, numerous equivalents to thespecific procedures, embodiments, claims, and examples described herein.Such equivalents are considered to be within the scope of this inventionand covered by the claims appended hereto. The contents of allreferences, issued patents, and published patent applications citedthroughout this application are hereby incorporated by reference. Theinvention is further illustrated by the following examples, which shouldnot be construed as further limiting.

EXAMPLES

The Examples set forth herein below provide exemplary syntheses ofcertain representative compounds of the invention. Also provided areexemplary methods for assaying the compounds of the invention for invitro stability, microsomes metabolism and mouse bioavailability.

Unless otherwise indicated, all numbers expressing quantities ofingredients, reaction conditions, concentrations, properties, and soforth used in the specification and claims are to be understood as beingmodified in all instances by the term “about.” At the very least, eachnumerical parameter should at least be construed in light of the numberof reported significant digits and by applying ordinary roundingtechniques. Accordingly, unless indicated to the contrary, the numericalparameters set forth in the present specification and attached claimsare approximations that may vary depending upon the properties sought tobe obtained. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of the embodiments are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containcertain errors resulting from variations in experiments, testingmeasurements, statistical analyses and such.

The present invention also relates to novel compounds and the synthesisthereof. The following detailed examples describe how to prepare thevarious compounds and/or perform the various processes of the inventionand are to be construed as merely illustrative, and not limitations ofthe preceding disclosure in any way whatsoever. Those skilled in the artwill promptly recognize appropriate variations from the procedures bothas to reactants and as to reaction conditions and techniques. In somecases, the compounds may be commercially available.

Example 1-A: Chemical Synthesis of Amino Acid Prodrugs

Accordingly, the following examples are presented to illustrate how someamino acid prodrugs according to the invention compounds may beprepared.

Preparation of N-Hydroxysuccinimide Ester

To a stirred solution of a N-Boc-protected amino acid or a carboxylicacid (10 mmol) in CH₂Cl₂ (100 mL) was added HBTU(N,N,N′,N′-Tetramethyl-O-(1H-benzotriazol-1-yl)uroniumhexafluorophosphate, 4.17 g, 11 mmol) followed by addition oftriethylamine (1.53 mL, 11 mmol) and N-hydroxysuccinimide (NHS, 1.26 g,11 mmol). The reaction mixture was stirred at room temperature for 4 h,and then diluted with HCl (1 N) and EtOAc (ethyl acetate). The organiclayer was isolated, dried over Na₂SO₄, and concentrated. The residualmaterial was purified by flash chromatography on silica gel usinghexanes-EtOAc as eluent to afford the corresponding N-hydroxysuccinimideester in good yield (about 70 to 88%).

General Procedures for the Preparation of Amino Acid Prodrugs of3-Amino-1-Propanesulfonic Acid (Procedures A to D)

Procedures A to D were used in different combinations, to produceexemplary compounds of the invention. Results for the preparation ofCompounds A to Y using these procedures are summarized in Table 2 below.

Procedure A

A solution of the N-hydroxysuccinimide ester of a N-Boc-protected aminoacid or a carboxylic acid (48 mmol, 1.2 eq) in acetonitrile or acetone(50 mL) was added slowly to a solution of 3APS,3-amino-1-propanesulfonic acid, 40 mmol, 1 eq in 2 N NaOH (sodiumhydroxide, 23 mL, 1.2 eq). The reaction mixture was stirred at roomtemperature overnight. The mixture was evaporated to dryness. Theresidual material was stirred with Et₂O (diethyl ether, 150 mL) atreflux for 1 h. After the mixture was cooled to room temperature, thesolid material was filtered and dried in vacuo, and further purifiedaccording to one of the following work-up procedures:

-   -   (i) The solid material was dissolved in water (25 mL). The        solution was passed through a Dowex™ Marathon™ C ion-exchange        column (strongly acidic, 110 g (5 eq), pre-washed). The strong        acidic fractions were combined and treated with concentrated HCl        (10 mL). The mixture was stirred at 50° C. for 30 minutes, and        then was concentrated to dryness. The residual material was        co-evaporated with EtOH (ethanol) to completely remove water.        EtOH (100 mL) was added to the residue. The mixture was stirred        at reflux for 1 h, and then cooled to room temperature. The        solid material was collected by filtration. The solid material        was dissolved in water (10 mL). The solution was added drop wise        to EtOH (100 mL). The product slowly crystallized. The        suspension was stirred at room temperature for 30 minutes. The        solid material was collected by filtration and it was dried in a        vacuum oven (60° C.).    -   (ii) The solid material was dissolved in water (25 mL). The        solution was passed through a Dowex™ Marathon™ C ion exchange        column (strongly acidic, 110 g (5 eq), pre-washed). The strong        acidic fractions were combined and evaporated under reduced        pressure. The residue was purified using reverse-phase flash        chromatography (Biotage™ SP-1, C18 column). For ester-containing        compound, the final product was obtained after removal of the        solvent from the corresponding fractions; otherwise go to (iii).    -   (iii) The residual material from step (ii) above was stirred        with 4N HCl (3 mL) at 50° C. for 1 h. A white solid precipitate        appeared. After the mixture was cooled to room temperature, the        solid material was collected by filtration, washed, and dried in        vacuo, to provide the final product.        Procedure B

To a stirred solution of a N-hydroxysuccinimide ester (3 mmol) in amixture of H₂O/tetrahydrofuran/CH₃CN (10/10/10 mL) was added a solutionof 3APS (as sodium salt) (3.3 mmol) in water (5 mL) followed by additionof 1M solution of potassium carbonate (3 mL). The reaction mixture wasstirred for 2 h, followed by addition of EtOAc. The aqueous layer wasisolated and concentrated to a residue. The residual material waspurified by silica gel column using CH₂Cl₂-MeOH (80-20) as eluent togive the corresponding N-Boc-protected product. The purifiedN-Boc-protected product was dissolved in dichloromethane (CH₂Cl₂, 10 mL)followed by addition of TFA (trifluoroacetic acid, 5 mL). The reactionmixture was stirred for 2 h, and then concentrated under reducedpressure. The residual solid material was suspended in a minimum amountof ethanol and the mixture was stirred for 1 h under reflux. The mixturewas cooled to room temperature. The solid material was collected byfiltration, washed with ethanol, and dried under high vacuum to affordthe final compound.

Procedure C

To the purified product containing benzyl ether protection group fromprocedure A or B (3.5 mmol) in 2N HCl (500 mL) and MeOH (500 mL) wasadded 10% Pd/C (2.15 g). The mixture was stirred under hydrogen (1 atm)overnight. The suspension was filtered (Celite™. The filter cake waswashed with water (2×25 mL). The filtrate and the washing were combinedand evaporated under reduced pressure. The residual material waspurified by reverse-phase HPLC (C18 column, 0-15% acetonitrile/water).The fractions containing the desired compound were combined andlyophilized, to give the final product.

Procedure D

This procedure is used to produce prodrugs of Formulae I to VI havingmore than one amino acid coupled to 3APS. Step (i) or (ii) is repeatedas necessary to obtain the desired compound.

-   -   (i) The product from Procedures A, B, or C is further reacted        with another N-hydroxysuccinimide ester following Procedure        A(i).    -   (ii) The product from Procedures A, B, or C was further reacted        with another N-hydroxysuccinimide ester following Procedure B.

TABLE 5 Synthesis and characterization of exemplary amino acid prodrugsaccording to the invention Synthetic NMR (ppm; 1H 500 MHz; 13C 125 MHz)ID Procedure MS (electrospray ionization) A1 A(i) 1H NMR (D2O) δ1.55-1.61 (m, 2H), 2.40-2.48 (m, 2H), 2.92-3.01 (m, 2H), 3.04-3.14 (m,2H), 3.95-3.98 (m, 1H), 7.11 (d, J = 6.8 Hz, 2H), 7.197.27 (m, 3H); 13CNMR (D2O) δ 23.76, 37.02, 38.21, 48.36, 54.79, 128.19, 129.33, 129.42,134.01, 168.94; m/z 285 (M − 1). A2 A(i) 1H NMR (D2O) δ 0.87-0.90 (m,6H), 1.83 (qt, J = 7.2 Hz, 2H), 2.02-2.09 (m, 1H), 2.79 (t, J = 7.8 Hz,2H), 3.20-3.29 (m, 2H), 3.60 (d, J = 6.3 Hz, 2H); 13C NMR (D2O) δ 17.20,17.77, 24.11, 30.00, 38.29, 48.63, 58.96, 169.35; m/z 237 (M − 1). A3A(i) 1H NMR (D2O) δ 1.82 (qt, J = 7.2 Hz, 2H), 1.90-1.95 (m, 3H),2.28-2.33 (m, 1H), 2.78 (t, J = 7.8 Hz, 2H), 3.22-3.33 (m, 4H), 4.21 (t,J = 7.1 Hz, 2H); 13C NMR (D2O) δ 23.95, 24.07, 29.85, 38.49, 46.57,48.53, 60.00, 169.64; m/z 235 (M − 1). A4 A(ii) 1H NMR (D2O) δ 1.30 (qt,J = 8.1 Hz, 2H), 1.57 (qt, J = 7.8 Hz, 2H), 1.75-1.85 (m, 4H), 2.77-280(m, 2H), 2.87 (t, J = 7.8 Hz, 2H), 3.17 (qt, J = 6.7 Hz, 1H), 3.31 (qt,J = 6.8 Hz, 1H), 3.83 (t, J = 6.6 Hz, 1H); 13C NMR (D2O) δ 21.47, 24.12,30.49, 38.30, 39.18, 48.63, 53.28, 169.66; m/z 266 (M − 1). A5 B 1H NMR(DMSO-d6) δ 0.81 (d, J = 7.3 Hz, 3H), 7.84 (d, J = 7.3 Hz, 3H), 1.5 (m,1H), 1.60 (m, 2H), 1.82 (m, 2H), 2.80 (m, 2H), 3.20-3.30 (m, 2H), 3.82(t, J = 7.3 Hz, 1H); 13C NMR (DMSO-d6) δ 21.48, 21.78, 24.17, 38.42,40.08, 48.66, 52.35, 170.53; m/z 251 (M − 1). A6 A(i) 1H NMR (D2O) δ1.84 (m, 2H), 1.99 (s, 3H), 2.04 (m, 2H), 2.47 (m, 2H), 2.80 (m, 2H),3.24 (t, J = 6.6 Hz, 2H), 3.94 (t, J = 6.6 Hz, 2H); 13C NMR (D2O) δ14.18, 24.07, 28.44, 30.09, 38.41, 48.61, 52.66, 169.46; m/z 269 (M −1). A7 B and C 1H NMR (D2O) δ 1.81 (m, 2H), 2.80 (m, 2H), 3.23 (m, 2H),3.80 (m, 2H), 3.97 (t, J = 5.0 Hz, 1H); 13C NMR (D2O) δ 24.10, 38.39,48.55, 54.85, 60.44, 167.97; m/z 22 (M − 1). A8 A(i) 1H NMR (D2O) δ 3.90(q, 1H, J = 7 Hz), 3.23 (t, 2H, J = 7 Hz), 2.78 (m, 2H), 1.82 (m, 2H),1.38 (d, 3H, J = 7 Hz); 13C NMR (D2O) δ 170.90, 49.30, 48.55, 38.28,24.10, 16.65; m/z 209 (M − 1). A9 A(i) 1H NMR (D2O) δ 3.90 (q, 1H, J = 7Hz), 3.23 (t, 2H, J = 7 Hz), 2.78 (m, 2H), 1.82 (m, 2H), 1.38 (d, 3H, J= 7 Hz); 13C NMR (D2O) δ 170.90, 49.30, 48.55, 38.28, 24.10, 16.65; m/z209 (M − 1). A10 B 1H NMR (D2O) δ 1.82 (m, 2H), 2.80 (m, 2H), 3.25 (m,2H). 3.67 (s, 2H); 13C NMR (D2O) δ 24.13, 38.26, 40.57, 48.55, 167.08;m/z 195 (M − 1). A11 A(i) 1H NMR (D2O) δ 0.80 (t, 3H, J = 7.3 Hz), 0.86(d, 3H, J = 6.8 Hz), 1.12 (m, 1H), 1.40 (m, 1H), 1.83 (m, 3H), 2.79 (m,2H), 3.25 (m, 2H), 3.68 (d, 1H, J = 5.9 Hz); 13C NMR (D2O) δ 10.59,14.22, 24.11, 24.37, 36.38, 38.29, 48.64, 58.00, 169.35; m/z 251 (M −1). A12 A(i) 1H NMR (D2O) δ 1.84 (m, 2H), 1.99 (s, 3H), 2.04 (m, 2H),2.47 (m, 2H), 2.80 (m, 2H), 3.25 (t, J = 7.3 Hz, 2H), 3.94 (t, J = 6.6Hz, 1H); 13C NMR (D2O) δ 14.18, 24.06, 28.42, 30.07, 38.41, 48.60,52.66, 169.42; m/z 269 (M − 1). A13 A(i) 1H NMR (D2O) δ 1.70 (m, 2H),2.64 (m, 2H), 3.15 (m, 1H), 3.22 (m, 3H), 4.06 (t, J = 6.3 Hz, 1H), 7.30(s, 1H), 8.55 (d, J = 1.5 Hz, 1H); 13C NMR (D2O) δ 23.94, 26.27, 38.36,48.43, 52.59, 118.40, 126.36, 134.60, 167.96; m/z 275 (M − 1). A14 A(i)1H NMR (D2O) δ 1.46 (s, 6H), 1.83 (m, 2H), 2.77 (m, 2H), 3.23 (t, J =6.6 Hz, 2H); 13C NMR (D2O) δ 23.44, 24.08, 38.54, 48.61, 57.21, 173.20;m/z 223 (M − 1). A15 A(i) 1H NMR (D2O) δ 1.74 (m, 2H), 2.59 (m, 2H),3.15 (m, 1H), 3.23 (m, 1H), 4.95 (s, 1H), 7.38 (m, 5H); 13C NMR (D2O) δ24.00, 38.35, 48.38, 56.84, 128.05, 129.87, 130.52, 132.46, 168.90; m/z271 (M − 1). A16 A(i) 1H NMR (D2O) δ 1.49 (m, 2H), 2.34 (m, 2H), 2.98(m, 2H), 3.21 (m, 2H), 4.01 (m, 1H), 7.05 (t, 1H, J = 7.3 Hz), 7.14 (m,2H), 7.39 (d, 1H, J = 8.3 Hz), 7.47 (m, 1H); 13C NMR (D2O) δ 23.60,27.14, 38.32, 48.16, 54.12, 106.83, 112.32, 118.23, 119.70, 122.35,125.18, 126.63, 136.37, 139.57; m/z 324 (M − 1). A17 A(iii) and 1H NMR(D2O) δ 1.66 (m, 2H), 2.58 (m, 2H), 2.92 (m, 1H), 3.04 (m, 2H), then C3.17 (m, 1H), 3.95 (t, 1H, J = 6.3 Hz), 6.77 (d, 2H, J 8.8 Hz), 7.02 (d,2H, J = 8.3 Hz); 13C NMR (D2O) δ 23.91, 36.29, 38.25, 48.42, 54.95,116.07, 125.88, 130.91, 155.29, 169.56; m/z 301 (M − 1). A18 B 1H NMR(D2O) δ 1.77 (m, 2H), 2.74 (m, 2H), 3.19 (, m2H), 3.75 (m, 2H), 4.05 (m,1H), 4.42 & 4.65 (AB, J = 12.2 Hz, 2H), 7.26-7.33 (m, 5H); 13C NMR (D2O)δ 24.10, 38.43, 53.23, 67.39, 73.28, 128.63, 128.67, 128.96, 136.86,167.55; m/z 315 (M − 1). A19 A(ii) 1H NMR (D2O) δ 7.3-7.2 (m, 5H), 5.05(s, 2H), 3.83 (t, J = 6.7 Hz, 1H), 3.21 (qn, J = 7 Hz, 1H), 3.08 (qn, J= 7 Hz, 1H), 2.78 (t, J = 7.8 Hz, 2H), 2.45 (t, J = 7 Hz, 2H), 2.05 (q,J = 7 Hz, 2H), 1.78 (m, 2H); m/z 357 (M − 1). A20 B 1H NMR (D2O) δ1.78-1.85 (m, 4H), 2.24 (t, J = 7.5 Hz, 2H), 2.79 (m, 2H), 2.88 (t, J =7.8 Hz, 2H), 3.18 (t, J = 7.0 Hz, 2H). 13C NMR (D2O) δ 23.21, 24.16,32.70, 38.16, 38.98, 48.65, 175.06; m/z 223 (M − 1). A22 1H NMR (D2O) δ1.84 (qn, 2H, J = 7 Hz), 2.78 (dd, 2H, J = 8.0, 6 Hz), 2.85 (ABX, 2H, J= 5.5, 7.3, 16.8 Hz), 3.24 (m, 2H), 3.61 (dd, 1H, J = 5.5, 7.3 Hz); 13CNMR (D2O) δ 24.05, 35.42, 38.46, 48.53, 50.04, 169, 171. A28 1H NMR(D2O) δ 0.8-0.9 (m, 12H), 1.81 (m, 1H), 1.88 (m, 1H), 2.09 (m, 2H), 2.77(t, 2H, J = 8.0 Hz), 3.20 (t, 2H, J = 6.6 Hz), 3.73 (d, 1H, J = 6.1 Hz),3.87 (d, 1H, J = 8.9 Hz); 13C NMR (D2O) δ 16.93, 17.82, 18.36, 24.21,29.77, 30.27, 38.08, 48.72, 58.42, 60.66, 169.45, 173.07

Example 1-B: Chemical Synthesis of Carbamate Prodrugs

Accordingly, the following examples are presented to illustrate how somecarbamate prodrugs according to the invention compounds may be prepared.

General Synthetic Procedures

Procedure A

Preparation of Compound C1 Sodium Salt(3-(p-acetyloxybenzyloxycarbonyl)amino-1-propanesulfonic Acid SodiumSalt)

Step 1: Acetyl chloride (3.0 mL, 42 mmol, 1 eq.) was added to a mixtureof 4-hydroxybenzylalcohol (5.3 g, 42 mmol), sodium hydroxide (1.7 g, 42mmol, 1 eq.) and tetrabutylammonium hydrogen sulfate (7 g, 0.5 eq.) indioxane (100 mL). The reaction mixture was stirred at room temperaturefor 4 hours and the solvent was evaporated. The residue was dissolved inwater and the aqueous phase was extracted with EtOAc (3 times). Combinedorganic extracts were washed with brine, dried and concentrated to givecolorless oil. Purification (flash chromatography; hexane/EtOAc,gradient mode) provided the corresponding monoacetate (2.2 g, 32%).

Step 2: Anhydrous pyridine (1.1 mL, 13 mmol, 1 eq.) was added drop wiseto a stirred mixture of p-nitrophenyl chloroformate (4.0 g, 20 mmol, 1.5eq.) and the monoacetate (from step 1: 2.2 g, 13 mmol) in drytetrahydrofuran (THF, 25 mL). A white precipitate was formed. Thereaction mixture was stirred at room temperature for 1 hour. The solidmaterial was removed by filtration, and washed with THF. The filtrateand the washing were combined; and the solvent was removed in vacuo. Theresidual material was purified by flash chromatography (hexanes/EtOAc,80/20) to provide the corresponding carbonate (2.8 g, 62%).

Step 3: The carbonate prepared in the step 2 (2.2 g, 6.7 mmol, 2 eq.)was added to a mixture of 3-amino-1-propanesulfonic acid sodium salt(538 mg, 3.32 mmol) and triethylamine (0.90 ml, 6.7 mmol, 2 eq.) in dryN,N-dimethylformamide (DMF, 10 mL). The reaction mixture was stirred atroom temperature overnight. Solvent was removed by evaporation. Theresidue was partitioned between EtOAc and water. The aqueous phase waswashed twice with EtOAc, and then lyophilized. HPLC purification(acetonitrile/water, 20/80 to 90/10) of the lyophilized residue providedthe title compound (396 mg, 33%): ¹H NMR (500 MHz, D₂O) δ ppm 1.83-1.89(m, 2H), 1.98 (s, 3H), 2.84-2.87 (m, 2H), 3.19-3.21 (m, 2H), 5.01 (s,2H), 7.03 (d, J=8.8 Hz, 2H), 7.32 (d, J=8.3 Hz, 2H).

Procedure B Preparation of Compound C6 Sodium Salt(4-aza-7-methyl-15-phenyl-11,11-tetramethylene-6,8,14-trioxa-5,9,13-trioxo-1-pentadecanesulfonicAcid Sodium Salt)

Step 1: 3,3-Tetramethyleneglutaric acid monobenzyl ester (4.26 g; 15.4mmol, prepared by heating overnight the cyclic anhydride and benzylalcohol in dioxane at 80° C. in the presence of triethylamine) andsilver oxide (2.13 g; 9.22 mmol) were added to a mixture of acetonitrile(40 mL) and water (20 mL). The mixture was heated at 70° C. for 3 h, andthen cooled to room temperature. The mixture was filtered through a padof Celite™. The filtrate was evaporated to provide the crude silvercarboxylate (2.19 g, 37%) which was used in the next step withoutfurther purification.

Step 2: A mixture of the silver carboxylate (2.19 g, 5.71 mmol; fromstep 1) and the carbamating reagent (1.00 g; 2.95 mmol; for preparation,see in Procedure E), in dry toluene (100 mL) was heated at 50° C.overnight. The mixture was filtered through a pad of Celite™ and thefiltrate was evaporated to provide a solid residue, which was purifiedby flash chromatography using hexane/EtOAc (80/20), giving the desiredintermediate product (0.915 g, 64%).

Step 3: To a solution of the intermediate product from step 2 (0.915 g;1.88 mmol) in dry DMF (5 mL) was added 3-amino-1-propanesulfonic acidsodium salt (300 mg; 1.85 mmol). The mixture was stirred at roomtemperature overnight. Solvent was removed by evaporation. The residualmaterial was purified by Prep-HPLC to furnish, after lyophilization, thetitle compound (632 mg, 66%): ¹H NMR (CD₃OD, 500 MHz) δ 1.39 (d, J=5.9Hz, 3H), 1.64-1.59 (m, 8H), 1.97-1.91 (m, 2H), 2.49 (qAB, J=15.1 Hz,2H), 2.57 (qAB, J=15.1 Hz, 2H), 2.82-2.79 (m, 2H), 5.10 (s, 2H),3.26-3.14 (m, 2H), 6.74 (q, J=5.9 Hz, 1H), 7.38-7.29 (m, 5H).

Other compounds prepared according to this procedure (Procedure B) werepurified either by precipitation using methanol and ether (protocol(b)), or by preparative HPLC using acetonitrile/water (10/90 to 90/10)over 40 minutes at 50 mL/min (protocol (a)), or by normal phase flashchromatography (protocol (c)).

Procedure C

Preparation of Compound C2 Sodium Salt(4-aza-12-carboxy-6,8-dioxa-5,9-dioxo-7-methyl-11,11-tetramethylene-1-dodecanesulfonicAcid Sodium Salt)

The corresponding benzylester of the title compound (344 mg; 0.678 mmol)in methanol (5 mL) was hydrogenolyzed in the presence of Pd/C 10% (100mg) at 40-45 psi for 1 h. The mixture was filtered (Celite™ and thefiltrate was evaporated to dryness. The residual material was dissolvedin water and the aqueous solution was lyophilized, giving the titlecompound (242 mg, 86%): ¹H NMR (CD₃OD, 500 MHz) δ 1.43 (d, J=5.4 Hz,3H), 1.66-1.63 (m, 8H), 1.98-1.92 (m, 2H), 2.49 (qAB, J=15.6 Hz, 2H),2.55 (qAB, J=15.1 Hz, 2H), 2.83-2.80 (m, 2H), 3.24-3.21 (m, 2H), 6.77(q, J=5.4 Hz, 1H), 7.22 (t, J=5.4, N—H).

Procedure D

Preparation of Compound C19 Sodium Salt(4-aza-7-methyl-6,8,-dioxa-5,9,-dioxo-1-decanesulfonic Acid Sodium Salt)

Step 1: 1-Chloroethylchloroformate (7.8 ml, 72 mmol, 1 eq.) was added toan ice-cold solution of p-nitrophenol (10 g, 72 mmol) in chloroform (100mL), followed by drop wise addition of pyridine (8.8 ml, 108 mmol, 1.5eq.) over a period of 20 min. The mixture was stirred in the ice-coldbath for 15 min, and then at room temperature overnight. The reactionmixture was sequentially washed with water, 1 N hydrochloric acid,water, 1 N sodium hydroxide, water, and brine. The organic phase wasdried over Na₂SO₄, and concentrated to give yellow oil which, uponstanding, crystallized to afford the corresponding chloroethyl carbonate(15.5 g, 88%).

Step 2: To a solution of the chloroethyl carbonate obtained from step 1(6.2 g, 25 mmol) in acetic acid (150 mL) was added mercuric acetate (9.6g, 30 mmol, 1.2 eq.). The mixture was stirred at room temperatureovernight. Solvent was evaporated. The residual material was transferredinto ether and washed with a saturated aqueous solution of NaHCO₃. Theether layer was dried over MgSO₄ and concentrated to give thick yellowoil. Purification of the oil by flash chromatography (hexane/EtOAc,95/5) gave the corresponding acetyloxyethyl carbonate (6.3 g, 94%) ascolorless oil.

Step 3: The acetyloxyethyl carbonate obtained from step 2 (1.2 g, 4.3mmol, 1.1 eq.) was added to a solution of 3-amino-1-propanesulfonic acidsodium salt (0.63 g, 3.9 mmol) in DMF (10 mL). The yellow solution wasstirred at room temperature overnight (color disappeared at this point).Solvent was evaporated. The residue was triturated several times withether and turned to a solid. The solid material was collected byfiltration to give the title compound (840 mg, 74%): ¹H NMR (500 MHz,CD₃OD) δ 1.42 (d, J=5.4 Hz, 3H), 1.92-1.98 (m, 2H), 2.02 (s, 3H),2.80-2.83 (m, 2H), 3.20-3.24 (m, 2H), 6.73 (q, J=5.4 Hz, 1H)

Other compounds prepared according to this procedure (Procedure D) werepurified either by extraction from EtOAc/water followed bylyophilization of the aqueous phase, or reverse-phase HPLC purificationusing acetonitrile/water (10/90 to 90/10) in 40 minutes at 50 mL/min, ortrituration/precipitation with ether.

Procedure E

Preparation of Compound C16 Sodium Salt(4-aza-7-methyl-6,8,-dioxa-5,9,-dioxo-9-phenyl-1-nonanesulfonic AcidSodium Salt)

Step 1: Sodium iodide (14 g, 92 mmol, 3 eq.) was added to a mixture ofthe chloroethyl carbonate (7.5 g, 31 mmol; for preparation, see inProcedure D), and grinded calcium chloride (10 g, 92 mmol, 3 eq.) inacetonitrile (100 mL). The reaction mixture was stirred at 40° C. for 4days, followed by filtration through a Celite™ pad. The filtrate wasconcentrated to give a red gummy residue. Purification by flashchromatography using EtOAc/hexane in a gradient mode provided thecorresponding iodoethyl carbonate (6 g, 59%) as pale yellow oil.

Step 2: Silver benzoate (5.5 g, 24 mmol, 2 eq.) was added to a solutionof the above-obtained iodoethyl carbonate (4 g, 12 mmol) in toluene (50mL). The reaction mixture was stirred at 55° C. overnight. The reactionmixture was filtered through a Celite™ pad and washed with toluene. Thefiltrate was concentrated to give brown oil. Two repeated purificationsby flash chromatography using hexane/EtOAc (90/10) provided thecorresponding benzoate (0.98 g, 25%) in high purity.

Step 3: The above-obtained benzoate (0.98 g, 2.9 mmol, 1.1 eq., fromstep 2) was added to a solution of 3-amino-1-propanesulfonic acid sodiumsalt (0.43 g, 2.7 mmol) in DMF (10 mL). The yellow solution was stirredat room temperature overnight. Solvent was evaporated and the residuewas dissolved in water. The aqueous solution was extracted several timeswith EtOAc. The aqueous phase was lyophilized to give a residue, whichwas purified by preparative HPLC (acetonitrile/water; 10/90 to 90/10, in40 minutes at 50 mL/min), giving the title compound (256 mg): ¹H NMR(500 MHz, D₂O) δ 1.48 (d, J=5.4 Hz, 3H), 1.76-1.82 (m, 2H), 2.76-2.79(m, 2H), 3.08-3.14 (m, 2H), 6.83 (q, J=5.4 Hz, 1H), 7.39-7.42 (m, 2H),7.55-7.58 (m, 1H), 7.89-7.91 (m, 2H).

Procedure F

Preparation of Compound C26 Sodium Salt(3-({[(5-methyl-2-oxo-1,3-dioxol-4-yl)methoxy]carbonyl}amino)-1-propanesulfonic Acid Sodium Salt)

A mixture of the sodium salt of 3-amino-1-propanesulfonic acid (532 mg;3.30 mmol) and the carbonate (1.10 g; 3.73 mmol; ref., J. Med. Chem.,1996, 39, 480-486) in dry DMF (10 mL) was stirred at room temperatureovernight. Solvent was removed in vacuo. To the residual material wasadded methanol (10 mL), followed by the addition of ether (75 mL). Thesolid formed was collected by filtration and dried overnight. Again thesolid was dissolved in methanol (10 mL) and precipitated with ether (50mL). The solid material was purified by preparative HPLC to provide thetitle compound (260 mg, 25%) as a white lyophilized solid: ¹H NMR(CD₃OD, 500 MHz) δ 1.98-1.92 (m, 2H), 2.17 (s, 3H), 2.90-2.79 m, 2H),3.22 (t, J=6.8 Hz, 2H), 4.86 (s, 2H).

TABLE 6 Synthesis and characterization of exemplary carbamate prodrugsaccording to the invention Synthetic Purifying m/z (ES⁻) ID procedureprotocol* (M − H, or M − Na)^(†) C1 A (a) 330.0 C2 C (d) 394.0 C3 B, C(a) 408.5 C4 C (d) 326.1 C5 B (a) 416.0 C6 B (a) 484.0 C7 B (a) 458.3 C8C (d) 368.5 C9 C (d) 354.0 C10 B (a) 444.1 C11 C (d) 340.1 C12 B (b) and(a) 430.2 C13 B (b) and (a) 378.0 C14 B (b) and (a) 372.0 C15 D (a)310.2 C16 E (a) 330.2 C17 D (a) 336.2 C18 D (b) 296.2 C19 D (b) 268.1C20 D (a) 378.1 C21 D (a) 310.1 C22 D (a) 296.1 C23 D (a) 338.1 C24 D(a) 310.0 C25 E (b) 253.9 C26 F (b) and (a) 294.0 *(a), HPLC; (b),precipitation; (c), flash chromatography; (d), filtration; (e),extraction, ^(†)the compounds were synthesized as acid form, or assodium salt form.

Example 1-C: Chemical Synthesis of Non-Amino Acid Amide Prodrugs

Accordingly, the following examples are presented to illustrate how somenon-amino acid amide prodrugs according to the invention compounds maybe prepared.

Procedure A

Preparation of Compound B3 Sodium Salt(3,3-dimethyl-5-oxo-5-[(3-sulfopropyl)amino]pentanoic Acid Sodium Salt)

A mixture of the 3,3-dimethylglutaric anhydride (1.0 g; 7.0 mmol) and3-amino-1-propanesulfonic acid sodium salt (0.950 g; 5.86 mmol) in dryDMF (20 mL) was stirred at 50° C. for 2 days. Solvent was evaporated. Tothe residual material was added methanol (=10 mL) followed by theaddition of ether (=50 mL) to cause precipitation. The precipitateformed was collected by filtration and then dissolved in water andlyophilized to provide the title compounds (1.33 g, 75%) as a powder: ¹HNMR (D₂O, 500 MHz) δ 0.94 (s, 6H), 1.82-1.77 (m, 2H), 2.14 (s, 3H), 2.23(s, 3H), 2.79-2.76 (m, 2H), 3.16 (t, J=6.8 Hz, 2H).

Other compounds prepared in the above procedure (Procedure A, see Table7) were purified either by methanol-ether precipitation (Purificationprotocol (b)), or using preparative HPLC (Purification protocol (a)), orby normal-phase flash-chromatography (Purification protocol (c)).Reaction time for Compounds B1 and B2 was 4 days; and for all othercompounds, 2 days.

Procedure B

Preparation of Compound B7 (3-[3-(2-Hydroxy-((S)-valylester)-4,6-dimethyl-phenyl)-3-methyl-butyrylamino]-1-propanesulfonicAcid)

Step 1: EDC (N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide) (6.4 g, 33mmol, 3 eq.) was added, at 0° C., to a 150-mL dry dichloromethanesolution containing Boc-Val-OH (4.9 g, 22 mmol, 2 eq.), the silylatedphenol (3.6 g, 11 mmol; ref., J. Med. Chem., 2000, 43, 475-487), andDMAP (4-(dimethylamino)pyridine, 5.5 g, 45 mmol, 4 eq.). The reactionmixture was stirred at room temperature overnight, then diluted withdichloromethane, and washed with a saturated aqueous solution of NaHCO₃,1N HCl, and brine subsequently. The organic layer was dried andconcentrated to a colorless oil residue. Purification of the residualmaterial (flash chromatography; using hexane/EtOAc, 95/5) gave thecorresponding intermediate (5.7 g, 99%) as a colorless oil.

Step 2: The intermediate from step 1 (5.7 g, 11 mmol) was stirred in amixture of THF-water-acetic acid (20 mL/20 mL/60 mL) at room temperaturefor 3 h; then the solvent was removed and the residue dried in vacuo.The residual material (the free alcohol) obtained was used in the nextstep without further purification

Step 3: A solution of the alcohol (11 mmol, from step 2) indichloromethane (125 mL) was slowly added to a suspension of PCC(pyridinium chlorochromate, 5.0 g, 23 mmol, 2.1 eq.) in drydichloromethane (125 mL). The reaction mixture was stirred at roomtemperature overnight. Solvent was evaporated and the residue wasdissolved in a minimum amount of dichloromethane. The resultingdichloromethane solution was passed through a silica gel column usingHexane/EtOAc (50/50). Evaporation of the solvent gave the correspondingaldehyde as yellow oil which was directly used in the next step withoutfurther purification.

Step 4: A solution of 80% sodium chlorite (2.5 g, 28 mmol, 2.5 eq.) inwater (10 mL) was added slowly to a solution of the aldehyde (11 mmol,form step 3) and sodium dihydrogen phosphate (818 mg, 6.8 mmol, 0.6 eq.)in acetonitrile (20 mL) and water (20 mL) at 0° C. The mixture wasstirred 1 h at 0° C. then at room temperature for 1 h. Sodium sulfite(1.5 g, 1 eq.) was added to decompose peroxides, and the pH was adjustedto 2 with 1N HCl solution. Reaction mixture was extracted twice withEtOAc. The organic layers were washed with brine, dried, andconcentrated. Purification of the residual material (flashchromatography; CH₂Cl₂/CH₃OH, 100/0 to 95/5) gave the correspondingcarboxylic acid (3.4 g, 73%) as a foam.

Step 5: EDC (908 mg, 4.75 mmol, 2 eq.) was added to a mixture of thecarboxylic acid (1 g, 2 mmol; from step 4), 3-amino-1-propanesulfonicacid sodium salt (380 mg, 2.34 mmol) and a catalytic amount of DMAP inDMF (10 mL). The reaction mixture was stirred at room temperatureovernight. Solvent was removed and the residue was dried in vacuo toprovide the corresponding derivative of 3-amino-1-propanesulfonic acidwhich was used in the next step without further purification.

Step 6: Trifluoroacetic acid (5 mL) was added to a solution of the3-amino-1-propanesulfonic acid derivative (2.4 mmol, from step 5) indichloromethane (5 mL) at room temperature. The reaction mixture wasstirred for 2 h, followed by evaporation of the solvent. The resultedresidue was purified (preparative HPLC; acetonitrile/water, 5/95 to70/30 in the presence of 0.01% TFA) to yield, after lyophilization, thetitle compound (0.3 g, 29%) as a white solid: ¹H NMR (500 MHz, D₂O)

1.04 (d, J=7 Hz, 3H), 1.07 (d, J=7 Hz, 3H), 1.39 (s, 3H), 1.45 (s, 3H),1.55-1.58 (m, 2H), 2.11 (s, 3H), 2.43 (s, 3H), 2.45-2.58 (m, 5H),2.98-3.02 (m, 2H), 4.26 (d, J=4 Hz, 1H), 6.54 (d, J=1.5 Hz, 1H), 6.93(d, J=1.5 Hz, 1H).

Procedure C

Preparation of Compound B14:3-{[(3α,5β,7α,12α)-3,7,12-trihydroxy-24-oxo-cholan-24-yl]amino}-1-propanesulfonicAcid

To a mixture of (+)-cholic acid (5.0 g, 12.2 mmol),3-amino-1-propanesulfonic acid sodium salt (1.85 g, 11.5 mmol),4-dimethylaminopyridine (72 mg, 0.6 mmol) in DMF (30 mL) was addedN-(3-dimethylaminopropyl)-1V-ethylcarbodiimide hydrochloride (EDC, 4.68g, 24.4 mmol). The reaction mixture was stirred at room temperatureovernight. The cloudy mixture was filtered through sintered glass beforethe solvent was evaporated to dryness under reduced pressure. Theviscous residue was dissolved in water (30 mL). The solution was treatedwith Dowex Marathon C™ ion exchange resin (strongly acidic, 30 g,pre-washed). The suspension was stirred for 15 minutes before the resinwas removed by filtration. The filtrate was concentrated to drynessunder reduced pressure and dried in vacuo. The residue was trituratedwith diethyl ether (1000 mL). The solid product was recovered byfiltration and dried in vacuo. The crude product was purified by flashchromatography (Biotage™ SP1: 20-40% EtOH in CH₂Cl₂) and thecorresponding fractions were collected and lyophilized, affording thetitle compound (178 mg, 3%); ¹H NMR (D₂O, 500 MHz) δ ppm 0.73 (s, 3H),0.93 (s, 3H), 1.02 (m, 4H), 1.31 (m, 7H), 1.52 (d, 1H, J=14.5 Hz), 1.65(m, 6H), 1.79 (m, 3H), 1.94 (m, 3H), 2.04 (m, 3H), 2.23 (m, 1H), 2.31(m, 1H), 2.92 (m, 2H), 3.31 (m, 2H), 3.52 (m, 1H), 3.92 (s, 1H), 4.08(s, 1H); ¹³C NMR (D₂O, 125 MHz) δ ppm 12.31, 16.82, 22.33, 23.12, 24.30,26.48, 27.47, 27.95, 29.37, 31.87, 32.71, 34.06, 34.54, 35.09, 35.33,38.15, 38.49, 39.50, 41.29, 41.64, 46.27, 46.28, 48.73, 68.33, 71.69,73.14, 177.44; m/z (ES⁺) 530; [α]_(D)=+25.7° (c=0.005, water).

TABLE 7 Synthesis and characterization of exemplary non-amino acid amideprodrugs according to the invention Synthetic Purifying m/z (ES⁻) IDprocedure protocol* (M − H, or M − Na)^(†) B1 A (a) 320.4 B2 A (a) 306.5B3 A (b) 280.2 B4 A (c) 280.3 B5 A (b) 238.0 B6 A (b) 525.0 B7 B (a)441.3 B9 B (a) 491.4 B10 B (a) 457.3 B11 B** (a) 514.2 B13 B** (a) 548.1*(a), HPLC; (b), precipitation; (c), flash chromatography; (d),filtration; (e), extraction; **Procedure B, replacing 3-APS byN-glycyl-3-APS; ^(†)the compounds were synthesized as acid form, or assodium salt form.

Example 1-D: Chemical Synthesis of Carbohydrate-Derived Prodrugs

Accordingly, the following examples are presented to illustrate how somecarbohydrate-derived prodrugs according to the invention compounds maybe prepared.

Synthesis of Compound S1 Sodium Salt

A suspension of glucose (2 g, 11.1 mmol) and the sodium salt of 3APS(2.24 g, 11.1 mmol) in MeOH (10 mL) was refluxed for 30 min before beingcooled down to room temperature. After 24 h of stirring at roomtemperature, the solid was filtrated and washed twice with MeOH (2×10mL). The resulting solid was dried overnight under high vacuum andafford the sodium salt of Compound S1 (3.1 g, 9.6 mmol, 86%) as a whitesolid. ¹H NMR (D₂O) (500 MHz) δ ppm 4.55 (d, J=4.4 Hz, 0.33H, α-anomer),3.87 (d, J=9.3 Hz, 0.66H, α-anomer), 3.74 (dd, J=12.2, 1.5 Hz, 0.66H),3.70 (dd, J=12.7, 2.4 Hz, 0.33H), 3.61 (dd, J=12.2, 4.9 Hz, 0.33H), 3.56(dd, J=12.2, 5.4 Hz, 0.66H), 3.53-3.49 (m, 1H), 3.33 (t, J=9.3 Hz,0.66H), 3.25-3.20 (m, 1H), 3.05 (t, J=8.8 Hz, 0.33H), 2.83 (m, 2.66H),2.68 (m, 1H), 2.57 (m, 0.33H), 1.78 (m, 2H). m/z (ES) 300.0 (M-H).

Synthesis of Compound S2

Methyl 6-bromo-6-deoxy-α-D-glucopyranoside was prepared according toTetrahedron 1991, 28(47), 5185-5192.

Step 1:

A stirred suspension of bromide (1 g, 3.89 mmol) and sodium azide (278mg, 4.28 mmol) in DMF (10 ml) was stirred at 90° C. for 5 days. Afterbeing cooled down to room temperature, the solution was evaporated undervacuum and the residue was purify by chromatography on silica gel(CHCl₃/MeOH 95/5 to 70/30 linear gradient) to afford the desired azido(776 mg, 3.54 mmol, 91%) as a white solid.

Step 2:

A solution of the previously prepared azido derivative (776 mg, 3.54mmol) in MeOH (10 ml) was degazed with N₂ for 10 min before a suspensionof 10% Pd/C (50 mg) in CHCl₃ was added. After being stirred 2 h under H₂pressure (40 PSI), the solution was filtrated over a pad of Celite™(MeOH) and evaporated under vacuum and afforded the desired amine (628mg, 3.25 mmol, 92% crude) as a yellow oil. This compound was used in thenext step without further purification.

Step 3:

A solution of sultone (285 μl, 3.25 mmol) in CH₃CN (5 ml) was added dropwise (over 30 min) to a refluxing solution of the previously preparedamine (628 mg, 3.25 mmol) in a 2/1 mixture CH₃CN/EtOH (10 ml). Theresulting solution was heated under reflux for 15 h before being cooleddown to room temperature and evaporated under vacuum. The residue waspurified by chromatography on silica gel (i-PrOH/H₂O (0.5% NH₄OH) 98/2to 80/20 linear gradient). After Evaporation, the compound was passedthrough a C-8 pad (H₂O) and lyophilized and afforded Compound S2 (450mg, 1.43 mmol, 44% over two steps) as a white solid. NMR ¹H (D₂O) (500MHz): 2.06 (m, 2H), 2.92 (t, J=7.0 Hz, 2H), 3.13 (m, 3H), 3.21 (t, J=9.5Hz, 1H), 3.34 (s, 3H), 3.36 (dd, 12.5, 3 Hz, 1H), 3.48 (dd, J=9.5, 3.5Hz, 1H), 3.56 (t, J=9.0 Hz, 1H), 3.77 (dt, J=9.0, 2.5 Hz, 1H), 4.74 (d,J=3.5 Hz, 1H). ES (MS) 314.1 (M-H). [α]_(D)=+86.3 (c 1.0, H₂O)

Procedure A: General Procedure for the Deprotection of 1,2,3,4- or2,3,4,6-Tetraacetate Glucose Derivative

To a stirred solution of the protected glucose derivative was addedenough of a solution of NaOMe (sodium methoxide, 0.5M in MeOH) in orderto obtain a basic pH (8-9, pH paper). The resulting solution was stirredat room temperature until completion (the reactions were generallyfollowed by MS) before addition of twice the initial volume of CH₃CN.The resulting solid was then filtrated and washed several time withCH₃CN, acetone and diethyl ether. The resulting solid was then passedtrough a C8 column (0.5% NH₄OH in H₂O) and lyophilized to afford thedesired compound.

Synthesis of Compounds S3 and S4

Step 1:

A suspension of the sodium salt of 3-amino-1-propanesulfonic acid (398mg, 2.47 mmol) and glucopyranuronic anhydride (398 mg, 2.47 mmol) in DMF(15 mL) was stirred 3 days at room temperature before evaporation of thesolvent under vacuum. The residue was purified by chromatography onsilica gel (CHCl₃/MeOH 100/0 to 70/30 linear) to afford compound S3 (719mg, 1.49 mmol, 60%) as a white foam. ¹H NMR (CD₃OD, 500 MHz) δ ppm 1.96(m, 2H), 1.98 (s, 3H), 2.01 (s, 3H), 2.02 (s, 3H), 2.09 (s, 3H), 2.83(m, 2H), 3.31 (m, 2H), 4.19 (d, J=9.5 Hz, 1H, H₅), 5.12 (t, J=8 Hz, 1H,H₂), 5.19 (t, J=10 Hz, 1H, H₄), 5.38 (t, J=9 Hz, 1H, H₃), 5.87 (d, J=8.5Hz, 1H, H₁). m/z (ES) 482.4 (M-H); [α]_(D)=+6.2 (c 0.93, MeOH).

Step 2:

Compound S3 (190 mg, 0.54 mmol) was treated according to Procedure A toafford Compound S4 (150 mg, 0.48 mmol, 88%) as a white solid. ¹H NMR(D₂O, 500 MHz) δ ppm 1.92 (m, 2H), 2.90 (m, 2H), 3.27 (t, J=8.5 Hz,0.5H), 3.32 (m, 2H), 3.47-3.50 (m, 1.5H), 3.56 (dd, J=9.5, 4.0 Hz,0.5H), 3.69 (t, J=9.0 Hz, 0.5H), 3.86 (d, J=7.0 Hz, 0.5H), 4.16 (d,J=10.0 Hz, 0.5H), 4.6-4.7 (0.5H, under water peak), 5.25 (d, J=3.5 Hz,0.5H); m/z (ES⁻) 314.4 (M-H).

Synthesis of Compound S5 Sodium Salt and Compound S6 Ammonium Salt

2,3,4,6-Tetra-O-acetyl-D-glucose was prepared according to J. Am. Chem.Soc. 1993, 115, 2260-2267.

Step 1:

p-nitrophenolchloroformate (638 mg, 3.16 mmol) was added to a stirredsolution of tetraacetylglucose (1 g, 2.87 mmol) and Et₃N (800 μl, 5.74mmol) in CH₂Cl₂ (20 ml) and the reaction was stirred overnight at roomtemperature. A 1N aqueous solution of hydrochloric acid (10 ml) wasadded and the layers were separated. The aqueous layer was extractedtwice with CH₂Cl₂ (20 ml) and the combined organic layer were washedsubsequently with a saturated solution of sodium carbonate (10 ml) and asaturated solution of sodium chloride. The organic layer was then dryover MgSO₄, filtrated and the solvent was evaporated under vacuum. Theresidue was purified by chromatography on silica gel (Hex/EtOAc 90/10 to5050, linear gradient) to afford the desired carbonate (1.108 g, 2.16mmol, 75%) as colorless solid.

Step 2:

Pyridine (524 ml, 6.48 mmol) was added to a suspension of the carbonatepreviously prepared (1.108 g, 2.16 mmol) and the sodium salt of 3APS(522 mg, 2.16 mmol). After 3 days of stirring at room temperature, thesolvent was evaporated under vacuum and the residue was purified bychromatography on silica gel (CHCl₃/MeOH 100/0 to 80/20, lineargradient) to afford Compound S5-Sodium salt (1.066 g, 2.07 mmol, 96%) asa white solid. ¹H NMR (D₂O, 500 MHz) δ ppm 1.97 (s, 3H), 2.00 (s, 3H),2.01 (s, 3H), 2.1 (m, 2H, hide), 2.05 (s, 3H), 2.83 (m, 2H), 3.25 (m,2H), 3.98 (br d, J=8.0 Hz, 0.4H, H₅b), 4.09 (t, J=10.5 Hz, 1H, H₆), 4.17(br d, J=10.2 Hz, 0.6H, H_(5a)), 4.26-4.30 (m, 1H, H₆), 4.99-5.12 (m,2H, H_(2a), H_(2b), H_(4b), H_(4a)), 5.32 (t, J=9.5 Hz, 0.40H, H_(3b)),5.50 (t, J=9.9, 0.6H, H_(3a)), 5.69 (d, J=8.4 Hz, 0.3H, H_(1b)), 6.17(d, J=3.5 Hz, 0.6H, H_(1a)). m/z (MS) 512.5 (M-H).

Step 3:

Compound S5 Sodium salt (500 mg, 0.97 mmol) was treated according toProcedure A to afford Compound S6-ammonium salt (220 mg, 0.64 mmol, 66%)as a white solid. ¹H NMR (D₂O (500 MHz) δ ppm 1.80 (m, 2H), 2.80 (m,2H), 3.15 (m, 2H), 3.30-3.37 (m, 1.5H), 3.41-3.43 (m, 1H), 3.68-3.53 (m,3H), 3.75 (d, J=12.2 Hz, 0.5H), 5.26 (d, J=8.2 Hz, 0.5H, H_(1b)), 5.82(d, J=3.05H2, 0.5H, H_(1a)). m/z (ES) 344.4 (M-H).

Synthesis of the Sodium Salt of Compound S7

2-(p-nitrophenylcarbamate)-ethyl-2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside was preparedaccording to Org. Lett. 2000, 2(8), 1093-1096.

Step 1:

3APS-sodium salt (223 mg, 1.38 mmol) was added to a stirring solution ofp-nitrophenyl carbamate (643 mg, 1.16 mmol) in DMF (7 mL). After 24 h ofstirring at room temperature, the solvent was evaporated under vacuumand the residue was purified by chromatography on silica gel (CHCl₂/MeOH100/0 to 70/30, linear gradient) and afforded the desired sulfonate (596mg, 1.07 mmol, 92%) as a white solid.

Step 2:

The 2,3,4,6-tetra-O-acetyl-D-glucose previously prepared (596 mg, 1.07mmol) was treated according to Procedure A to afford Compound S7-sodiumsalt (260 mg, 0.67 mmol, 63%) as a white solid. ¹H NMR (D₂O, 500 MHz) δppm 1.91 (m, 2H, H11), 2.93 (t, J=7.5 Hz, 2H, H12), 2.24 (t, J=6.0 Hz,H10), 3.28 (t, J=9.0 Hz, 1H, H2), 3.34 (m, 2H, H8), 3.38 (t, J=9.5 Hz,1H, H4), 3.45 (ml, 1H, H6a), 3.49 (dd, J=9, 9 Hz, 1H, H3), 3.7-3.77 (m,2H, H6a, H7a), 3.91 (apparent d, J=11.5 Hz, H5, H7b), 4.46 (d, J=8.0 Hz,H1). m/z (ES) 386.9 (M-H).

Synthesis of the Sodium Salt of Compounds S8 and S9

N-(9-Fluorenylmethoxycarbonyl)-3-O-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-L-serinePentafluorophenyl ester was prepared according to J. Med. Chem. 1995,38, 161-169.

Step 1:

SAPS-sosium salt (258 mg, 1.60 mmol) was added to a stirring solution ofpentaflurophenyl ester (1200 mg, 1.45 mmol) in DMF (15 mL). After 24 hof stirring at room temperature, the solvent was evaporated under vacuumand the residue was purified by chromatography on silica gel (CHCl₃/MeOH100/0 to 80/20, linear gradient) to afford the desired sulfonate (1070mg, 1.37 mmol, 94%) as a white solid.

Step 2:

Piperidine (2.7 mL, 27 mmol) was added to a stirred solution ofpreviously prepared Fmoc serine derivative (1070 mg, 1.37 mmol) in DMF(15 mL). After stirred for 1 h, solvent was evaporated under reducedpressure. The residue was purified by chromatography on silica gel(CHCl₃/MeOH 100/0 to 75/25, linear gradient) to afford the desired amineCompound S8-sodium salt (350 mg, 0.63 mmol, 46%) as a white solid.

Step 3:

The 2,3,4,6-tetra-O-acetyl-D-glucose previously prepared (350 mg, 0.63mmol) was treated according to Procedure A to afford Compound S9-sodiumsalt (210 mg, 0.54 mmol, 86%) as a white solid. ¹H NMR (D₂O, 500 MHz)1.95 (m, 2H, H11), 2.94 (t, J=8.0 Hz, 2H, H12), 3.35 (dd, J=7.5, 9.0 Hz,1H, H2), 3.36-3.41 (m, 3H, H4, H10), 3.42-3.50 (m, 2H, H3, H5), 3.73(dd, J=6.0, 1 H, 12.0 Hz, H6a), 3.92 (br d, J=12.0 Hz, 1H, H6b), 3.96(dd, J=4.5, 1H, 11.5 Hz, H8), 4.05 (t, J=4.5 Hz, 1H, H7a), 4.22 (dd,J=4.5, 11.5 Hz, 1H, H7), 4.47 (d, J=7.5 Hz, 1H, H1). m/z (ES) 387.25(M-H).

Synthesis of the Sodium Salt of Compounds S14 and S15

1,2,3,4-tetra-O-acetyl-α-D-glucopyranoside was prepared according toOrg. Lett. 2006, 8, 2393-2396 and J. Am Chem. Soc. 2000, 122,12151-12157.Step 1:

p-Nitrophenolchloroformate (3 g, 14.8 mmol) was added to a stirredsolution of 1,2,3,4-tetra-O-acetyl-α-D-glucopyranoside (4.7 g, 13.4mmol) and triethylamine (3.7 ml, 26.8 mmol) in dichloromethane (100 mL).The reaction mixture was stirred overnight at room temperature. A 1Naqueous solution of hydrochloric acid (30 mL) was added and the layerswere separated. The aqueous layer was extracted twice withdichloromethane (100 mL) and the combined organic layers were washedsubsequently with a saturated solution of sodium carbonate (50 mL) andthen with a saturated solution of sodium chloride. The organic layer wasdried over magnesium sulfate, filtered and the solvent was evaporatedunder vacuum. The residue was purified by chromatography on silica gel(hexanes/ethyl acetate 90/10 to 50/50, linear gradient), affording thecorresponding carbonate (4.7 g, 68%) as a colorless solid.

Step 2:

The sodium salt of SAPS (2.22 g, 13.8 mmol) was added to a solution ofthe carbonate previously prepared (4.7 g, 9.16 mmol) inN,N-dimethylformamide (50 mL). After 3 days of stirring at roomtemperature, the solvent was evaporated under vacuum and the residue waspurified by chromatography on silica gel (dichloromethane/methanol 100/0to 70/30, linear gradient) and afforded Compound S15-sodium salt (1.95g, 41%) as a white solid together with its 1-deactetylated derivative(1.21 g, 36%) as a white solid: ¹H NMR (D₂O, 500 MHz) δ ppm 1.91-2.02(m, 11H), 2.07 (s, 2H), 2.17 (s, 1H), 2.86 (m, 2H, H1), 3.24 (t, J=8.0Hz, 2H, H3), 3.99 (m, 0.7H, H6β), 4.10-4.20 (m, 2.3H, H5 and H6α), 5.02(m, 1H, H9), 5.08 (t, J=10.0 Hz, 0.7H, H7β), 5.13 (t, J=9.5 Hz, 0.3H,H7α), 5.34 (t, J=9.5 Hz, 0.7H, H8β), 5.44 (t, J=9.5 Hz, 0.3H, H8α), 5.81(d, J=8.0 Hz, 0.7H, H10β), 6.28 (d, J=3.5 Hz, 0.3H, H10α); m/z (ES)512.0 (M-H).

Step 3:

Compound S15-sodium salt (1.37 g, 2.67 mmol)) was treated according toProcedure A to afford Compound S14-sodium salt (520 mg, 1.51 mmol, 56%)as a white solid: ¹H NMR (D₂O, 500 MHz) δ ppm 1.80 (m, 2H, H2); 2.81 (m,2H, H1), 3.12 (m, 2.55H, H3 and H9β); 3.31 (m, 1H, H7α and H7β); 3.36(m, 0.55H, H83); 3.41 (dd, J=10.0, 4.0 Hz, 0.45H, H9α); 3.48 (m, 0.55H,H6β); 3.56 (t, J=9.0 Hz, 0.45H, H8α); 3.84 (brd, J=10.0 Hz, 0.45H, H6α),4.10 (m, 1H, H5a), 4.23 (apparent t, J=12.5 Hz, 1H, H5b), 4.51 (d, J=8.0Hz, 0.55H, H10β); 5.08 (d, J=4.0 Hz, 0.45H, H10α); m/z (ES) 344.0 (M-H).

Synthesis of the Sodium Salt of Compounds S16 and S17

2,3,4,6-Tetra-O-acetyl-D-glucose-1-propanol was prepared according to J.Am. Chem. Soc. 1940, 62, 917-920.Step 1:

p-Nitrophenolchloroformate (2.3 g, 11.4 mmol) was added to a stirredsolution of 3-hydroxy-1-propyl2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside (3.1 g, 7.64 mmol) andtriethylamine (2.12 mL, 11.44 mmol) in dichloromethane (60 mL) and thereaction mixture was stirred overnight at room temperature. Aqueoushydrochloric acid (1N, 15 mL) was added and the layers were separated.The aqueous layer was extracted 2 times with dichloromethane (40 mL) andthe combined organic layer were washed subsequently with a saturatedsolution of sodium carbonate (15 mL) and then with a saturated solutionof sodium chloride. The organic layer was then dried over magnesiumsulfate, filtrated and the solvent was evaporated under vacuum. Theresidue was purified by chromatography on silica gel (hexanes/ethylacetate 90/10 to 50/50, linear gradient) to afford the correspondingcarbonate (3.1 g, 71%) as colorless solid.

Step 2:

The sodium salt of 3-APS (655 mg, 4.07 mmol) was added to a solution ofthe carbonate previously prepared (1.55 g, 2.71 mmol) inN,N-dimethylformamide (50 mL). After 3 days of stirring at roomtemperature, the solvent was evaporated under vacuum and the residue waspurified by chromatography on silica gel (dichloromethane/methanol 95/5to 70/30, linear gradient) to afford a mixture of Compound S17 andp-nitrophenol (1.33 g) as a white solid, which was used in next stepwithout further purification.

Step 3:

The crude Compound S17 (1.33 g) was treated according to Procedure A toafford Compound S16-sodium salt (850 mg, 49% over two steps) as a whitesolid: ¹H NMR (D₂O, 500 MHz) δ ppm 1.84-1.91 (m, 4H, H6+H2), 2.88 (m,2H, H1), 3.18 (m, 2H, H3), 3.21 (t, J=8.5 Hz, 1H, H9), 3.33 (t, J=9.3Hz, 1H, H11), 3.39 (m, 1H, H12), 3.44 (t, J=9.3 Hz, 1H, H10), 3.67 (dd,J=12.3, 5.8 Hz, 1H, H13a), 3.71 (m, 1H, H7a), 3.85 (dd, J=12.3, 2.0 Hz,1H, H13b), 3.94 (m, 1H, H7b), 4.10 (m, 2H, H5), 4.39 (d, J=8.0 Hz, 1H,H8); m/z (ES) 402.1 (M-H).

Example 1-E: Chemical Synthesis of Imine-Derived Prodrugs

Accordingly, the following examples are presented to illustrate how someimine-derived prodrugs according to the invention compounds may beprepared.

Synthesis of Compound M7 Sodium Salt

Sodium 3-amino-1-propanesulfonate (0.64 g, 4.0 mmol) was added to asolution of 4′-chloro-5-fluoro-2-hydroxy-benzophenone (0.50 g, 2.0 mmol)in methanol (50 mL). The reaction mixture was stirred under reflux for 4h then concentrated under reduced pressure. The residual material waspurified by flash chromatography (silica gel, chloroform:methanol 90:10then 80:20) to afford the title compound (0.51 g, 64%): ¹H NMR (CDCl₃,500 MHz) δ 1.89 (m, 2H), 2.5 (t, J=7.0 Hz, 2H), 3.36 (t, J=7.0 Hz, 2H),6.95 (m, 1H), 6.95 (m, 1H), 7.22 (m, 1H), 7.38 (d, J=8.0 Hz, 2H), 7.66(d, J=8.0 Hz, 2H), 15.27 (s, 1H). ES-MS (370 M-1).Synthesis of Compound M7-Sulfonamide

Step 1:

To a stirred solution of sodium azide (3.5 g, 50 mmol) in water (25 mL)was added a solution of 1,3-propane sultone (6.1 g, 50 mmol) in acetone(25 mL). The reaction mixture was stirred at room temperature for 24 hthen concentrated to dryness. The resulting solid was suspended indiethyl ether (100 mL) and stirred at reflux for 1 h. The suspension wascooled to room temperature and the solid was collected by filtration,washed with acetone and diethyl ether, and dried under vacuum, affordingof 3-azido-1-propanesulfonic acid (7.6 g, 80%).

Step 2:

PCl₅ (2.61 g, 12.53 mmol) was added to a suspension of3-azido-1-propanesulfonic acid (2.07 g, 12.53 mmol) in toluene. Thereaction mixture was stirred under reflux for 3 h. After cooling to roomtemperature, the solvent was evaporated, and the resulting material wasused in the next step without further purification.

Step 3:

Ammonium hydroxide (28%) (10 mL) was added to a solution of3-azido-1-propanesulfonyl chloride (˜2.29 g, 12.53 mmol; obtained instep 2) in ethanol (10 mL). The reaction mixture was stirred at roomtemperature for 3 h then concentrated. The residual material was passedthrough a short silica gel column using hexanes:ethyl acetate as eluentto isolate 3-azido-1-propanesulfonamide (1.5 g, 86%).

Step 4:

3-Azido-1-propanesulfonamide (1.5 g, 10.86 mmol; obtained from step 3)was dissolved in water/ethanol (10 mL/10 mL), followed by addition of10% Pd/C (0.2 g). The resulting suspension was stirred under atmosphericpressure of H₂ for 5 h. The insoluble material was removed byfiltration; and the filtrate was concentrated. The residual material wassuspended in hydrogen. The suspension was filtered and the resultingsolid was washed with ethanol and diethyl ether, dried under highvacuum, affording 3-amino-1-propanesulfonamide (1.2 g, 80%).

Step 5:

3-Amino-1-propanesulfonamide (0.55 g, 4 mmol; from step 4) was added toa solution of 4′-chloro-5-fluoro-2-hydroxy-benzophenone (1 g, 4 mmol) inmethanol (50 mL). The reaction mixture was stirred under reflux for 5 hthen concentrated under reduced pressure. The residual material waspurified by column chromatography (silica gel, dichloromethane:methanol90:10 then 80:20). The corresponding solid (after removal of solvent)was recrystallized in diethyl ether to afford3-{[(1E)-(4-chlorophenyl)(5-fluoro-2-hydroxyphenyl)methylene]amino}propane-1-sulfonamide(0.75 g, 51%). ¹H NMR (CDCl₃, 500 MHz) δ 2.21 (m, 2H), 3.24 (t, J=7.0Hz, 2H), 3.47 (t, J=7.0H, 2H), 4.63 (bs, 2H), 6.93 (m, 1H), 6.95 (m,1H), 7.04 (m, 1H), 7.13 (d, J=8.2 Hz, 2H), 7.54 (d, J=8.2 Hz, 2H), 14.71(s, 1H). ES-MS (369 M-1).

Example 2: In Vitro Stability and Metabolism

In vitro stability of exemplary prodrugs of the invention was tested inwater, in an acidic aqueous solution (pH: 1.5), in PBS, in human andmouse microsomes, and in human and mouse whole blood.

A. Stability in Water, at pH: 1.5 and PBS

Stability of exemplary compounds was determined in water, aqueous acidicsolution (pH 1.5, HCl) and PBS (phosphate buffered saline) solutionusing ESI-MS (electrospray ionization mass spectrometry) as thedetecting instruments. In general a 2 μg/mL pro-drug solution containing1 μg/ml IS (internal standard) was prepared and incubated for 60 min.For water stability the incubation was performed at room temperature andfor stability in acidic solution and in buffer. The incubationtemperature was 37° C. Samples were analyzed for prodrug content at timepoints 0 and 60 min. using MS. The % changes in peak area ratio after 60minutes for each test compound tested are calculated using the averagevalues from six replicate runs. The compounds tested included CompoundsA1 to A19, Compounds B5 and B6 and Compounds C1 to C26. Except for C26which was found unstable at pH 1.5 and in PBS, all other compounds werejudged to be stable under all conditions tested with less than about15%-20% concentration change after 60 minutes.

B. Metabolism in Mouse and Human Microsomes

Microsomal stability of Compounds A1, A2, A3, C17, C18 and C19 wasdetermined in duplicate, in presence of pooled mouse or human livermicrosomes for up to 60 minutes at 37° C. Briefly, microsomes werediluted to achieve a concentration of 1.0 mg/mL in PBS buffer (pH 7.4)containing 3 mM MgCl₂ and 1 mM EDTA. Compounds (10 μM) and microsomeswere pre-incubated for a period of 5 minutes before the enzymaticreaction was started by addition of co-factors (1 mM NADPH- and 2 mMUDPGA in PBS buffer). After a 1-hour incubation period, the reaction wasstopped by the addition of ice cold acetonitrile. For time 0 samples,the reaction was stopped with acetonitrile before the addition of theco-factors. Analysis of extracted samples was achieved using HPLC withMS detection. Several types of HPLC columns and mobile phases were useddepending of the polarity of the compound. The compound stability wasdetermined by the % of compound remaining at 60 minutes (peak responseof compound at 60 minutes/peak response at 0 minutes×100). Four of thecompounds tested (three amino acid prodrugs A1, A2, A3, and thecarbamate prodrug C19) were found stable, with over 90% of the compoundsremaining after 60 minutes in presence of mouse or human microsomes(data not shown). Compound C17 was found less stable with between 20 and35% of the prodrug remaining after 60 minutes in presence of mouse orhuman microsomes, while carbamate C18 showed moderate stability withbetween 75 and 80% of the prodrug remaining under the same conditions.

C. Mouse and Human Whole Blood Stability

Test compounds were incubated for a total of 240 minutes at 37° C. inwhole mouse and whole human blood. The compounds were added attime-point 0 and sample aliquots were withdrawn at each time point(usually 0, 60 and 240 minutes). The samples were extracted usingprotein precipitation. Analysis of extracted samples was achieved usingHPLC with MS detection. Several types of HPLC columns and mobile phasewere used depending of the polarity of the compound. The compoundstability was determined by the % of compound remaining at 240 minutes(peak response of compound at 240 minutes/peak response at 0minutes×100). Results are summarized in Table 8.

TABLE 8 Stability in mouse and human whole blood Blood stability (% ofcompound remaining after 240 min.) ID Human Blood Mouse Blood A1 ND + A2ND ++ A3 ND ++ A4 + +++ A5 + + A6 ++ + A7 +++ +++ A8 + ++ A9 +++ +++ A10++ ++ A11 +++ +++ A12 +++ +++ A13 +++ +++ A14 +++ +++ A15 ++ + A16 +++++ A18 + + A19 + + B3 +++ ++ B4 +++ +++ B5 +++ +++ B6 +++ +++ C1 + + C4+++ ++ C5 + + C7 +++ + C8 +++ +++ C9 ++ ++ C10 + + C11 +++ +++ C12 ++ +C13 + + C14 +++ ++ C15 ++ + C16 ++ + C17 ND + C18 ND + C19 ND + C20 ++ +C21 ++ + C22 ++ + C23 ++ + C24 ++ + +: <30%, ++: 30-75%, +++: >75%; ND:not determined

These data illustrate the use of these compounds as prodrugs, as theyare converted to 3APS in the blood.

Example 3: Pharmacokinetics in Mice

A. Bioavailability of Exemplary Compounds

Selected exemplary compounds were tested for bioavailability in mice.Bioavailability estimates are performed for 3APS after administration ofmolar equivalent the selected compounds. At a specific time pointfollowing drug administration, one blood sample (approximately 1 ml) iscollected from each of 3 animals from the inferior vena cava. Theanimals are anesthetized with isoflurane before blood collection(approximately 45 sec). Samples are collected at 5, 30, 60, 120, 180,240 and 360 min post intravenous administration and at 15, 30, 60, 120,180, 240 and 360 min post oral administration. One animal is used toobtain a baseline sample (pre-dose sample). Blood samples are collectedinto Sarstedt™ micro tubes (EDTA KE/1.3 ml), kept on ice untilcentrifugation at 4° C. at a minimum speed of 3000 rpm (1620G) for 10min. Plasma samples are transferred into Eppendorf™ tubes, immediatelyplaced on dry ice and stored at −80° C. Plasma samples are stored frozenat −20° C. pending analysis.

Compounds in mouse plasma are extracted using protein precipitation.Quantitation of 3APS in mouse plasma matrix is achieved using LC-MSdetection. Sample concentration is calculated using a calibration curve.Bioavailability results are summarized in Table 9.

TABLE 9 Bioavailability of selected compounds in mice Bioavailability(F) in mice* ID (+: <25%, ++: 25-35%, +++: >35%) A (3APS) ++ A1 ++ A2+++ A3 + A4 +++ A6 ++ A7 +++ A13 +++ A18 +++ C9 + C13 + C14 + C15 +C16 + C17 + C18 + C19 ++ C21 + C22 + C25 + *Calculated from theconcentration of 3APS, 6 hours after administration of the testedcompound. The calculated F value represents the Ratio (in percentage) ofthe AUC p.o. of the compound tested over the AUC i.v. of 3APS, based onthe observation of 3APS.

As shown in Table 9, all the compounds tested were capable of deliveringmeasurable quantities of 3APS. Compounds A2, A4, A7 and A18 were helpfulin increasing the bioavailability of 3APS suggesting that they were morereadily absorbed than 3APS or were able to prevent first-pass metabolismof 3APS. Although not shown, Compounds A3, C13, C14, C16, C17, C21, C22and C25 had a measured T_(max) 4 times to 16 times longer that 3APS(0.25 h), suggesting a significant improvement in the pk profiles of3APS using those compounds.

B. PK Brain and Plasma Levels of Oral Compound A2 and 3-APS

Compounds A2 and 3-aminopropanesulfonic acid were tested forpharmacokinetic parameters in mice. Parmacokinetic parameters (Cmax,Tmax, T1/2, AUC) are evaluated for 3APS after administration of a molarequivalent of each compound. Blood samples (approximately 1 ml) andbrain samples are collected from each of 3 animals at time points 5, 15,30 minutes, 1, 2, 4, 6, 12, and 24 hours. The results analyzed fromplasma samples and brain homogenates are summarized in Table 10.Relative bioavailability (F %) of Compound A2 and 3-APS wererespectively of 51% and to 32%. A 2-fold increase in plasmaconcentration (Cmax) of 3-APS was observed when orally administeringCompound A2 compared to 3-APS. Brain concentration of 3-APS was observedafter oral administration of 0.18 mmol/kg for Compound A2, whereas theconcentration could not be quantified after oral administration of thesame molar equivalent of 3-APS.

TABLE 10 PK data on 3-APS analysis following oral administration of 25mg/kg (0.18 mmol/kg) and 250 mg/kg (1.80 mmol/kg) equivalent of 3-APSPlasma Brain Dose Cmax Tmax T½ Cmax Tmax T½ ID (mmol/kg) AUC (ng/mL) (h)(h) AUC (ng/mL) (h) (h) 3-APS 0.18 6427 1768 0.5 4.9 BLLQ BLLQ N/A N/AA2 0.18 10135 3435 0.5 2.8 557 148 2.0 3.9 A2 1.80 140661 35451 0.5 2.89772 1068 2.0 12.4 BLLQ: below the lower limit of quantification N/A:not applicable

Example 4: Pharmacokinetic Analysis of 3APS and Associated MetabolismExample 4A: Metabolic Profiling of ¹⁴C-3APS in Mice, Rats and Dogs

Three single dose studies were conducted in mice, rats and dogs todetermine the metabolic profile of ¹⁴C-3APS in plasma, urine and feces.In the first study, twenty-seven male CD-1 mice received a single doseof 100 mg/kg (20 μCi/animal) of ¹⁴C-3APS by oral gavage. Blood samples(3 animals/time point) were collected for 12 hr following drugadministration while urine and feces (3 animals/time point) samples werecollected for 96 hr. In the second study, eight male Sprague-Dawley ratsreceived a single dose of 100 mg/kg (50 μCi/animal) of ¹⁴C-3APS by oralgavage while in the third study, three male Beagle dogs received asingle dose of 100 mg/kg (30 μCi/kg) of ¹⁴C-3APS by oral gavage. For therat and dog studies, blood samples were collected for 24 hr followingdrug administration while urine and feces samples were collected for 72hr. All samples were analyzed for total radioactivity using appropriatesample preparation procedures and scintillation counting. Plasma andurine samples were also analyzed for 3APS and SAPS metabolites(2-carboxyethanesulfonic acid, 3-hydroxy-1-propanesulfonic acid and3-acetylamino-1-propanesulfonic acid) concentrations using qualifiedHPLC and MS/MS methods.

Following oral administration of 100 mg/kg ¹⁴C-3APS to mice and rats,mean maximum plasma concentrations of total radioactivity and 3APS werereached at approximately 30 minutes post-dose (Table 11). Thereafter,plasma concentrations of total radioactivity and 3APS declined in amulti-phasic manner with apparent terminal half-lives of approximately 2and 6 h for mice and rats, respectively. Mean maximum plasmaconcentration of 2-carboxyethanesulfonic acid was achieved at 120 to 240h post-dose. Thereafter, plasma concentrations declined in amulti-phasic manner with an apparent terminal half-life of approximately2 h and 4 h for mice and rats, respectively.

Following oral administration of 100 mg/kg ¹⁴C-3APS to dogs, maximumplasma concentration of total radioactivity and 3APS were reached atapproximately 30 minutes post-dose, whereas maximum plasma concentrationof 2-carboxyethanesulfonic acid was achieved at 720 minutes post-dose(Table 11). Thereafter, plasma concentrations of total radioactivity and3APS declined in a multi-phasic manner. The mean apparent terminalhalf-lives were approximately 35 h and 5 h for total radioactivity and3APS, respectively.

For all species, the majority of total radioactivity was associated with3APS and 2-carboxyethanesulfonic acid (Table 12). Based on AUC_(0-∞)values, 3APS accounted for approximately 60% of total radioactivitywhile 2-carboxyethanesulfonic acid accounted for 30% in mice and rats.In dogs, 3APS accounted for approximately 54% of total radioactivitywhile 2-carboxyethanesulfonic acid accounted for approximately 67%. 3APSand 2-carboxyethanesulfonic acid AUC_(0-∞) constituted approximately 90%(mouse and rat) and approximately 121% (dog) of the total radioactivityindicating that 2-carboxyethanesulfonic acid is the major metabolite of3APS in the mouse, rat and dog.

For all species, total radioactivity was quantitatively recovered inurine and feces with approximately 75 to 90% of the administered doserecovered in 72 h (rat and dog) or 96 h (mouse). The major route ofexcretion of total radioactivity was via urine.

On average, 60% of the dose was excreted in urine as total radioactivityin all species. Based on the total amount of radioactivity excreted inurine, approximately 30% was excreted as 3APS while2-carboxyethanesulfonic acid accounted for another 63% to 77% in mouseand dog. In rats, 3APS and 2-carboxyethanesulfonic acid accounted for59% and 62% of total radioactivity, respectively. On average the twometabolites 3-hydroxy-1-propanesulfonic acid and3-acetylamino-1-propanesulfonic acid represented less than 3% of thetotal radioactivity in all species (Table 11). The urinary cumulativeamount of 3APS and 2-carboxyethanesulfonic acid accounted forapproximately 90 to 110% of that determined for total radioactivity,once again suggesting that 2-carboxyethanesulfonic acid is the majormetabolite of 3APS in the mouse, rat and dog.

TABLE 11 Pharmacokinetic Parameters of Total Radioactivity, 3APS and 2-carboxyethanesulfonic acid Following Single Oral Administration of 100mg/kg ¹⁴C-3APS in Mice, Rats and Dogs Parameter Mouse¹ Rat Dog TotalRadioactivity C_(max) (μmol eq/mL) 0.126 0.228 0.249 T_(max) (min) 30 3031 AUC_(0-τ) (μmol eq · min/mL) 24.4 43.3 45.4 AUC_(∞) (μmol eq ·min/mL) 25.0 45.2 108 T_(1/2) (h) 2.14 6.02 35.7 3APS C_(max) (μmol/mL)0.0977 0.218 0.250 T_(max) (min) 30 30 31 AUC_(0-τ) (μmol · min/mL) 15.526.7 24.5 AUC_(∞) (μmol · min/mL) 15.7 27.6 25.3 T_(1/2) (h) 1.72 6.435.04 2-carboxyethanesulfonic acid C_(max) (μmol/mL) 0.018 0.0234 0.0312T_(max) (min) 120 240 720 AUC_(∞-τ) (μmol · min/mL) 7.26 12.7 30.5AUC_(∞) (μmol · min/mL) 7.56 13.6 NC T_(1/2) (h) 2.33 3.99 NC ¹PKparameters were derived using the mean plasma concentration-timeprofiles NC: Not calculated

TABLE 12 Percentage of 3APS, 2-carboxyethanesulfonic acid,3-acetylamino-1- propanesulfonic acid and 3-hydroxy-1-propanesulfonicacid in Plasma and Urine Following Single Oral Administration of 100mg/kg ¹⁴C-3APS in Mice, Rats and Dogs % of Total Radioactivity3-acetylamino- 2- 1- 3-hydroxy-1- carboxyethanesulfonic propanesulfonicpropanesulfonic 3APS acid acid acid Mouse Plasma* 63 30 — — Urine^(†) 3062 3.1 0.4 Rat Plasma* 61 30 — — Urine^(†) 59 62 2.3 0.3 Dog Plasma* 5467 — — Urine^(†) 29 77  0.01 0.3 *Calculated as [AUC0-∞ 3APS ormetabolites/AUC total radioactivity)] (or using AUC0-t if AUC0-∞ couldnot be reliably estimated) ^(†)Calculated as [Amount Excreted 3APS ormetabolites/AUC total radioactivity)]

Example 4B: Absorption Excretion and Plasma Kinetics of ¹⁴C-3APS inHumans

Following the identification of 3APS metabolites, plasma and urinesamples from this human AME study were reanalyzed for 3APS and 3APSmetabolite (2-carboxyethanesulfonic acid, 3-hydroxy-1-propanesulfonicacid and 3-acetylamino-1-propanesulfonic acid) concentrations usingqualified HPLC and MS/MS methods to determine the metabolic profile of¹⁴C-3APS in human.

Following oral administration of ¹⁴C-3APS to healthy subjects, maximumplasma concentration of total radioactivity and 3APS were reached atapproximately 1 to 1.25 hours post-dose, whereas maximum plasmaconcentration of 2-carboxyethanesulfonic acid was achieved at 6.5 hours.In plasma, the majority of total radioactivity was associated with 3APSand 2-carboxyethanesulfonic acid. Based on AUC_(0-τ) values, 3APSaccounted for approximately 48% of total radioactivity while2-carboxyethanesulfonic acid accounted for 49%. 3APS and2-carboxyethanesulfonic acid AUC_(0-τ) constituted approximately 97% ofthe total radioactivity indicating that 2-carboxyethanesulfonic acid isthe major metabolite of 3APS in human plasma.

Based on the total amount of radioactivity excreted in urine,approximately 15% was excreted as 3APS while 2-carboxyethanesulfonicacid accounted for another 79%. The urinary cumulative amount of 3APSand 2-carboxyethanesulfonic acid accounted for approximately 94% of thatdetermined for total radioactivity, once again suggesting that2-carboxyethanesulfonic acid is the major metabolite of 3APS.

Example 4C: Comparative Pharmacokinetic Parameters of 3APS and2-Carboxyethanesulfonic Acid Following a Single Oral and IVAdministration of ¹⁴C-3APS to Rats

The purpose of this study was to investigate the absorption, metabolismand excretion profiles of ¹⁴C-3APS following a single intravenous bolusand oral administration to rats. Thirty-six male Sprague-Dawley ratsreceived a single 100 mg/kg (˜50 μCi/animal) dose of ¹⁴C-3APS by an IVbolus injection (water or isotonic saline solution) and an additional 36male rats received the same dose level by oral gavage (in water). Blood,urine, feces, brain and CSF samples were collected for up to 72 hrfollowing dose administration. Plasma, urine, brain and CSFconcentrations of 3APS and 2-carboxyethanesulfonic acid (3APS majormetabolite) were measured using LC and MS/MS detection method. Plasma,urine, feces, brain and CSF samples were analyzed for totalradioactivity using appropriate sample preparation procedures andscintillation counting.

Based on AUC_(0-∞) values, after IV administration, 3APS accounted for89% of total radioactivity and 2-carboxyethanesulfonic acid only about9%. On the other hand, after oral administration, 3APS accounted forabout 68% of total radioactivity and 2-carboxyethanesulfonic acid about26%. Using those data, it is possible to calculate ametabolite-to-parent ratio of the exposure of about 0.1 following IVadministration and a ratio of 0.38 following oral administration. Thishigher metabolite-to-parent ratio of the exposure following oraladministration when compared to IV is consistent with an intestinalfirst-pass metabolism.

TABLE 13 Comparison of Systemic Exposure of 3APS and2-carboxyethanesulfonic acid versus Total Radioactivity following aSingle IV and Oral Administration of 14C-3APS in Rats AUC_(0-∞) (nmol ·h/mL)^(#) % % 2- (2- (3APS and 2- carboxyethanesulfonic Totalcarboxyethane carboxyethanesulfonic Animal 3APS acid Radioactivitysulfonic acid)* acid)** IV 1001 1528 105 1625 6.5 100.5 1002 1420 1441588 9.1 98.5 1003 1591 184 1883 9.8 94.3 1004 1147 125 1266 9.9 100.5Mean 1422 140 1591 8.8 98.4 ±SD 196.2 33.7 253.0 1.60 2.93 % CV 13.824.1 15.9 18.1 2.98 PO 3001 610 232 874 26.5 96.3 3002 539 153 714 21.496.9 3003 407 177 628 28.2 93.0 3004 471 229 781 29.3 89.6 Mean 507 198749 26.4 94.0 ±SD 87.4 39.1 104 3.49 3.37 % CV 17.3 19.8 13.9 13.2 3.59^(#)AUC_(0-∞) expressed as nmol eq · h/mL for total radioactivity*Calculated as [(AUC_(0-∞) 2-carboxyethanesulfonic acid/AUC totalradioactivity) * 100] **Calculated as [(AUC_(0-∞) 3APS + AUC_(0-∞)2-carboxyethanesulfonic acid)/AUC total radioactivity] * 100

Example 4D: Comparative Pharmacokinetics Parameters of 3APS and2-Carboxyethanesulfonic Acid Following a Single Oral, Intravenous andPortal Administration of 3APS in Rats

The purpose of this study was to compare the pharmacokinetic profile of3APS following a single dose administration either orally, intravenouslyor into the portal vein to male Sprague-Dawley rats. The oral,intravenous and portal routes of administration were selected todetermine the intestinal and hepatic first-pass effects in the rat.Three groups of 4 male Sprague-Dawley rats were assigned to receive asingle dose of 250 mg/kg 3APS by different routes of administration. Onegroup received 3APS as an IV bolus administration (in water or isotonicsaline solution), one group by oral gavage (in water) and the last groupvia a catheter into the portal vein (in water or isotonic salinesolution). Blood samples were collected for 24 hours following doseadministration. Plasma concentrations of 3APS and2-carboxyethanesulfonic acid (the major metabolite of 3APS) weredetermined using LC and MS/MS method.

Following oral administration, maximum plasma concentrations (C_(max))were generally reached within 1 hour for 3APS and its bioavailabilitybased on the AUC_(∞) was calculated to be about 38%.

The results obtained confirmed that there is an important metabolism of3APS. More particularly, based on a comparison between the systemicexposures following hepatoportal and intravenous administrations,metabolism of 3APS associated with hepatic first-pass was estimated tobe 24%. By comparison between the systemic exposures following oral andhepatoportal administrations, metabolism of 3APS associated withintestinal first-pass was estimated to be 43%. This study also showedthat the oral administration of 3APS generated 50% more metabolite thanthe intravenous administration which is consistent with an intestinalfirst-pass metabolism.

Example 5: In Vitro Metabolism of 3APS in Primary Rat Neuron Culture andOrganotypic Hippocampal Slice Culture

The metabolism of 3APS was also studied in vitro in different types ofcellular models. In some cases, the metabolism of 3APS was compared withthat of γ-amino butyric acid (GABA).

The results obtained demonstrated that incubation of 3APS (400 μM) inprimary rat neuron culture media produced 2-carboxyethanesulfonic acidas a metabolite. The conversion of 3APS to 2-carboxyethanesulfonic acidwas time-dependent and cell concentration-dependent. Incubation of 3APS(400 μM initial concentration) for six days in the cell culture media(containing 800,000 cells) produced with 48 μM of2-carboxyethanesulfonic acid. Under the same experimental conditions,5.4 μM succinic acid was detected starting from GABA (400 μM initialconcentration).

The conversion of 3APS to 2-carboxyethanesulfonic acid in the primaryneuron culture media was significantly inhibited by vigabatrin, thelatter a classic GABA transaminase inhibitor. Nialamide, a monoamineoxidase inhibitor, also reduced the formation of 2-carboxyethanesulfonicacid (from 3APS) but to a lesser extent. In contrast, gabapentin (knownto increase GABA concentration in the brain) had no significant effecton the conversion of SAPS to 2-carboxyethanesulfonic acid.

In another in vitro model employing organotypic hippocampal sliceculture, the conversion of SAPS to 2-carboxyethanesulfonic acid wastime-dependent. More than 60% of SAPS was converted to2-carboxyethanesulfonic acid after 3-day incubation in the culturemedia. 2-carboxyethanesulfonic acid was also detected after incubationof SAPS in human hepatocyte (HepG2) culture media.

It is understood that the examples and embodiments described herein arefor illustrative purposes only and that various modifications or changesin light thereof will be suggested to persons skilled in the art and areto be included within the spirit and purview of this application andscope of the appended claims.

The invention claimed is:
 1. A compound of Formula VIII:

wherein said compound is selected from the group consisting of:

or a pharmaceutically acceptable salt of any of the foregoing.
 2. Apharmaceutical composition comprising a compound of claim 1 togetherwith a pharmaceutically acceptable carrier.
 3. The pharmaceuticalcomposition of claim 2 which is suitable for oral administration.
 4. Thepharmaceutical composition of claim 2, which is in the form of a hardshell gelatin capsule, soft shell gelatin capsule, cachet, pill, tablet,lozenge, powder, granule, pellet, dragee, which is optionally entericcoated, a solution, an aqueous liquid suspension, a non-aqueous liquidsuspension, an oil-in-water liquid emulsion, a water-in-oil liquidemulsion, an elixir, a syrup, or a pastille.
 5. A process for convertinga compound of claim 1 to 3-amino-1-propanesulfonic acid (3APS)comprising contacting said compound with plasma, blood, and/or braincells whereby said compound is metabolized to 3APS.
 6. A method fortreating Alzheimer's disease, mild cognitive impairment, Down'ssyndrome, Hereditary Cerebral Hemorrhage with Amyloidosis of theDutch-Type, cerebral amyloid angiopathy, a degenerative dementia, adementia of mixed vascular and degenerative origin, dementia associatedwith Parkinson's disease, dementia associated with progressivesupranuclear palsy, dementia associated with cortical basaldegeneration, or diffuse Lewy body type of Alzheimer's disease,comprising administering a therapeutically effective amount of acompound of claim 1 to a human subject in need thereof.
 7. The method ofclaim 6, which is for treating Alzheimer's disease, mild cognitiveimpairment, cerebral amyloid angiopathy, or degenerative dementia. 8.The method of claim 7, which is for treating Alzheimer's disease.
 9. Themethod of claim 6 wherein the compound is administered intratracheally,intranasally, ontologically, rectally, vaginally, or orally.